| Title |
Investigators | Department | Objectives | Approach Keywords | Progress Reports | Impact Statements | Publications | |
Project * COL00713 | |
| Title | Introduction, Adaptability, Production and Survival of Landscape Plants in Colorado |
| Investigator(s) | Klett, JE; |
| Department | Horticulture and Landscape Architecture |
| Objectives | 1. Selection, introduction and evaluation of herbaceous and woody plant material for growing in the Rocky Mountain and High Plains Region including Plant Select material. 2. Conduct cultural studies related to adaptability, production and survival of landscape plants in Colorado which can include: 2A. Evaluate production systems especially pot-in-pot production techniques. 2B. Weed control studies to aid in overall production of container grown landscape plants. 2C. Evaluate the compensation capacity of certain xeric plants. 2D. Identify and develop management strategies for mycorrhizal relationships in landscape plant establishment and growth. |
| Approach | 1. Selection, introduction and evaluation of herbaceous plant material for growing in the Rocky Mountain and High Plains region, including Plant Select. Trial plantings of annuals, herbaceous perennials and woody plants will continue to be conducted in Fort Collins to determine which plants are best suited for the Rocky Mountains and High Plains Area. Plant Select, a cooperative plant introduction program between Denver Botanic Gardens and Colorado State University, whose purpose is to increase the diversity of commercially available plants best suited for Rocky Mountain and High Plains regions, will continue. This program is identifying, selecting, testing, producing, introducing and promoting outstanding new plants adapted for landscape use. Criteria have been established for identification, selection and testing for these outstanding new plants. [2a] Compare and evaluate production systems and components of these systems, especially pot-in-pot production for landscape plants for Colorado. In Spring 2001, a multi-year research project was initiated to examine the possible benefits of pot-in-pot (PIP) production. After input from the Colorado Nurseryman Research and Education Foundation and the Colorado Nursery Industry, it was determined that PIP production systems could be used to increase overall quality and salability of trees in this region. PIP systems have been shown to increase growth of plants by extending the growing season. [2b] Weed control studies to aid in overall production and establishment of landscape plant material. Experiments studying the effect of herbicide types and rates especially with container grown herbaceous perennials and some woody nursery stock will be continued. New and standard herbicides and several combinations will be evaluated for their effectiveness on weed control, phytotoxicity and effects on plant growth. [2c] Cultural studies evaluating the compensation capacity of certain xeric plants. A study to assess the phenotypic plasticity found in O. macrocarpa ssp. incana and fremontii with respect to pubescence and cuticle color and how that plasticity responds to different abiotic factors will be initiated in 2002. In addition, this study will evaluate the capacity of these plants to compensate for reduced pubescence and reflectance with changes in other plant structures and floral traits. To isolate the effects associated with genetic variability, both clonal and seed propagated plants of O. macrocarpa ssp. incana and clones of O. macrocarpa ssp. fremontii will be grown under identical treatments. [2d] Identify and develop management strategies for mycorrhizal relationships and other factors in landscape plant production and utilization. A research project examining the inoculation of both newly planted and existing Fraxinus pennsylvanica `Marshall Seedless' (Marshall Seedless Green Ash) with various mycorrhizal products was initiated in Spring 2001 at two irrigated sites in Aurora, CO. |
| Keywords | plant-evaluation, Plant-Select, weed-control, woody-plant-production, post-plant-growth, mycorrhizal relationships, compensation capacity |
| Progress Reports | |
| 1993 | Woody and herbaceous plants continue to be evaluated for adaptability to High Plains on a 22 ha site. Woody Plants (104 taxa) and herbaceous plants (45 taxa) were acquired in 1993 for evaluation. Crabapples (75 clones) continue to be evaluated for fireblight resistance and landscape features. Performance records for 2530 taxa of woody and herbaceous plants were entered into a computer program. Acer grandidentatum seedlings from 14 northern sources were transplanted into number one containers for further evaluation for the Plant Select Program. Eight sources of Chrysothamnus were germinated for eventual selection for growth habit and foliage color. A third seed collection trip for Plant Select program was conducted in 1993 to collect Sorbus scopulina and Juglans microcarpa seed for hardiness and fall color. New and standard herbicides, isoxaben, metolachlor, napropamide, oryzalin, oxadiazon, oxyfluorfen + oryzalin and treflan were evaluated for their effectiveness of weed control and phytotoxic effect of 11 genera of container or field grown herbaceous perennials or woody plants. All herbicides tested controlled weeds effectively with no phytotoxicity except on two species. Phytotoxic symptoms appeared on Thymus pseudolanuginosus with metolachlor and isoxaben and on Syringa vulgaris with isoxaben. Research was initiated in 1993 to study wildflower weed control. Field plots were established and three methods of weed control are being examined. |
| 1994 | Woody and herbaceous plants continue to be evaluated for adaptability to High Plains on 22ha. Woody(135 taxa) and herbaceous plants(46 taxa) were acquired in 1994 for evaluation. Crabapples(75 clones) continue to be evaluated for fireblight resistance and landscape features. Performance records for 3937 taxa of woody and herbaceous plants were entered into a computer program. Acer grandidentatum seedlings (14 northern sources) were grown in number one containers for further evaluation for the Plant Select Program. Buds from the parent trees were collected in July 1994 and placed on Acer saccharum understock. Chrysothamnus (8 sources) are being grown for selection for growth habit and foliage color. New and standard herbicides, isoxaben, metolochlor, napropamide, oxyzaline, oxadiazon, oxyfluorfen + oryzalin and treflan were evaluated for their effectiveness of weed control and phytotoxic effect of 6 genera of container grown herbaceous perennials or woody plants. All herbicides controlled weeds effectively with no phytotoxicity except on two species. Phytotoxic symptoms appeared on Digitalis and Veronica with isoxaben. Wildflower weed control research initiated in 1993 showed that two treatments of post emergent herbicide prior to planting contributes to more weed free wildflower growth. Research was initiated in 1994 to determine water requirements of four herbaceous perennials and examine post-plant growth of woody plants under different water regimes. |
| 1995 | Woody & herbaceous plants continue to be evaluated for adaptability to High Plains on 22 ha. Woody(94 taxa) & herbaceous plants(69 taxa) were acquired in 1995 for evaluation. Crabapples(80 clones) continue to be evaluated for fireblight resistance & landscape features. Performance records for 1826 taxa of woody & herbaceous plants were entered into a computer program. Acer grandidentatum seedlings(14 northern sources) gained size for further evaluation in 1996. Chrysothamnus(8 sources) were field planted for evaluation of growth habit & foliage color. Selections of Juglans microcarpa & Sapindus drummondii were propagated for further evaluation. New & standard herbicides, isoxaben, napropamide, oryzalin, oxadiazon, oxyfluorfen + oryzalin & trifluralin were evaluated for their effectiveness of weed control & phytotoxic effect of 5 genera of container grown herbaceous perennials. All herbicides tested controlled weeds with no phytotoxicity except on 3 species. Phytotoxic symptoms appeared on Delosperma with oxadiazon & oxyfluorfen + oryzalin; Chrysanthemum with isoxaben & Festuca with oryzalin. Wildflower weed control research initiated in 1993 showed that elimination of weeds prior to sowing is important & trifluralin suppresses weed seeds but also wildflower seed germination. Research continued to determine water requirements of herbaceous plants & examining post plant growth of woody plants from different production techniques under various water regimes. |
| 1996 | Woody & herbaceous plants continue to be evaluated for adaptability to High Plains on a 22 ha site. Woody(119 taxa) & herbaceous plants(161 taxa) were acquired in 1996 for evaluation. Crabapples(80 clones) continue to be evaluated for fireblight resistance & landscape features. Performance records for 2060 taxa of woody & herbaceous plants were entered into a computer program. Acer grandidentatum seedlings (3 sources) were distributed to 27 sites for regional evaluation. Five plant species are being endorsed or introduced to the trade & public by Plant Select for 1996-97. Chrysothamnus (8 sources) are being field evaluated for growth habit & foliage color. New & standard herbicides, napropamide, oryzalin, oxadiazon, oxyfluorfen + oryzalin, oxyfluorfen + pendimethalin and trifluralin were evaluated for their effectiveness of weed control & phytotoxic effect on 5 genera of container grown herbaceous perennials. All herbicides tested controlled weeds with no phytotoxicity except on 3 species. Phytotoxic symptoms appeared on both Penstemon & Phlox with oryzalin at the 2x rate & on Dianthus with trifluralin at the 2x rate. Irrigation treatments resulted in Aquilegia having a decline in plant growth & appearance below 50% evapotranspiration(ET). Callirhoe at 50 & 75% ET displayed acceptable growth. Gaillardia & Gypsophilia displayed acceptable growth at 25% ET. Research continues on examining post plant growth of woody plants from different production techniques under different water regimes. |
| 1997 | Woody and herbaceous plants continue to be evaluated for adaptability to High Plains on a 22 ha site. Woody (82 taxa) and herbaceous plants (194 taxa) were acquired in 1997 for evaluation . Crabapples (80 clones) continue to be evaluated for fireblight resistance and landscape features. Performance records for 2,345 taxa of woody and herbaceous plants were entered into a computer program. Over 630 varieties of annual flowers were grown and evaluated during the 1997 season and a performance report was published and sent to all cooperators and industry personnel. Acer grandidentatum seedlings (3 sources) were distributed to 27 sites for regional evaluation and first year evaluation reports were received and recorded. Five plant species were recommended or introduced to the trade and public by Plant Select in 1997. Over 160,000 of these 1997 Plant Select plants were tagged or sold in 1997. In 1998, six plants are being recommended or introduced. Chrysothamnus (8 sources) continue to be field evaluated for growth habit and foliage color. New and standard herbicides, napropamide, oryzalin, oxadiazon, oxyfluorfen + oryzalin, oxyfluorfen + pendimethalin and trifluralin were evaluated for their effectiveness of weed control and phytotoxic effect of 5 genera of container grown herbaceous perennials. All herbicides tested controlled weeds with no phytotoxicity except on one species . Phytotoxic symptoms appeared on Phalaris arundinacea with napropamide at the 1x and 2x rates . Napropamide provided poor weed control with Scabiosa at both rates. All other treatments provided good weed control at both rates. A three year field study was started to study the impact of post harvest storage methods on physiological quality and transplant success of balled and burlapped Tilia cordata `Greenspire'. After one year the shrink wrap with mulch treatment was considered the most effective during the storage phase although transplant recovery is yet to be determined. First year results of a two year field study on mechanical root pruning and water stress indicate that root pruning of container grown perennials significantly reduces current year's growth (mean widths and densities). All four species of perennials could maintain both appearance and size under limited irrigation conditions 2.54 cm/6 days (avg daily ETo = 0.85cm). |
| 1998 | Woody and herbaceous plants continue to be evaluated for adaptability to High Plains on a 22 ha site. Woody (91 taxa) and herbaceous plants (48 taxa) were acquired in1998 for evaluation. Crabapples (85 clones) continue to be evaluated for fireblight resistance and landscape features. Performance records for 2,544 taxa of woody and herbaceous plants were entered into a computer program. Over 730 varieties of annual flowers were grown and evaluated during the 1998 season and a performance report was published and sent to all cooperators and industry personnel. Acer grandidentatum seedlings (3 sources) were distributed to 27 sites for regional evaluation and second-year evaluation reports were received and recorded. Six plant species were recommended or introduced to the trade and public by Plant Select in 1998. Over 255,000 of these 1998 Plant Select plants were tagged or sold in 1998. In 1999, eight plants are being recommended or introduced. Chrysothamnus (8 sources) continue to be field evaluated for growth habit and foliage color. New and standard herbicides, napropamide, oryzalin, oxadiazon, oxyfluorfen + oryzalin, oxyfluorfen + pendimethalin and trifluralin were evaluated for their effectiveness of weed control and phytotoxic effect of 8 genera of container-grown herbaceous perennials. All herbicides tested controlled weeds with no phytotoxicity except on one species . Phytotoxic symptoms appeared on Phalaris arundinacea with napropamide at the 1x and 2x rates . All other treatments provided good weed control at both rates. A three-year field study started in 1997 continued to study the impact of post harvest storage methods on physiological quality and transplant success of balled and burlapped Tilia cordata `Greenspire'. After one season in the field, it appears that mulching and containing root growth during storage appears to be beneficial to transplant success. Water stressing trees in storage appears to carry over into the transplanting phase the following year. Tree rooting into sand during storage had a negative effect on transplant recovery; whereas, those rooting into bark mulch were not affected negatively. |
| 1999 | Woody and herbaceous plants continue to be evaluated for adaptability to High Plains on a 22 ha site. Woody (55 taxa) and herbaceous plants (137 taxa) were acquired in1999 for evaluation. Performance records for 2,702 taxa of woody and herbaceous plants were entered into a computer program. Over 787 varieties of annual flowers were grown and evaluated during the 1999 season and a performance report was published and sent to all cooperators and industry personnel. Acer grandidentatum seedlings (3 sources) were distributed to 27 sites for regional evaluation and third-year evaluation reports were received and recorded. Eight plant species were recommended or introduced to the trade and public by Plant Select in 1999. Over 1.5 million Plant Select plants were tagged or sold since it started in 1997. In 2000, five plants are being recommended or introduced. Chrysothamnus (8 sources) continue to be field evaluated for growth habit and foliage color. New and standard herbicides, napropamide, oryzalin, oxadiazon, oxyfluorfen + oryzalin, oxyfluorfen + pendimethalin, trifluralin, prodiamine, and pendimethalin were evaluated for their effectiveness of weed control and phytotoxic effect of six genera of container-grown herbaceous perennials. All herbicides tested controlled weeds well with no phytotoxicity on any of the species. A three-year field study started in 1997 was continued to study the impact of post harvest storage methods on physiological quality and transplant success of balled and burlapped Tilia cordata `Greenspire'. After two seasons in the field, it appears that mulching and containing root growth during storage appears to be beneficial to transplant success. Water stressing trees in storage appears to carry over into the transplanting phase the first year after transplanting. Tree rooting into sand during storage had a negative effect on transplant recovery the first growing season; whereas, those rooting into bark mulch were not affected negatively. However, after two growing seasons in the field, all treatments had statistically equivalent annual shoot elongation. |
| 2000 | Woody and herbaceous plants continue to be evaluated for adaptability to High Plains on a 22 ha site. Woody (86 taxa) and herbaceous plants (84 taxa) were acquired in 2000 for evaluation. Performance records for 2,787 taxa of woody and herbaceous plants were entered into a computer program. Crabapples (90 clones) continue to be evaluated for fireblight resistance and landscape features. Over 950 varieties of annual flowers were grown and evaluated during the 2000 season and a performance report was published and sent to all cooperators and industry personnel. As a result of these trials, New Guinea Impatiens have become a more important annual flower crop in the state. Five plant species were recommended or introduced to the trade and public by Plant Select in 2000. Over 175,000 of the 2000 Plant Select plants were tagged or sold in 2000. In 2001, seven plants are being recommended or introduced. Chrysothamnus (8 sources) continue to be field evaluated for growth habit and foliage color. New and standard herbicides, oryzalin, oxadiazon, oxyfluorfen + oryzalin, oxyfluorfen + pendimethalin, benefin and trifluralin, prodiamine, and pendimethalin were evaluated for their weed control effectiveness and phytotoxic effect on six genera of container-grown herbaceous perennials and woody plants. All herbicides tested controlled weeds well with no major phytotoxicity. A three-year field study started in 1997 continued to study the impact of post harvest storage methods on physiological quality and transplant success of balled and burlapped Tilia cordata `Greenspire'. After three years in the field, it appears that any initial benefits of mulching and containing root growth during storage were no longer apparent . Any stress from storage techniques prior to transplanting was not significant. Growth increments show greater growth in the third year associated with fabric treatment and no differences between other treatments. |
| 2001 | Woody and herbaceous plants continue to be evaluated for adaptability to High Plains on a 22 ha site. Woody (55 taxa) and herbaceous plants (28 taxa) were acquired in 2001 for evaluation. Performance records for 3,023 taxa of woody and herbaceous plants were entered into a computer system. Crabapples (90 clones) continue to be evaluated for fireblight resistance and landscape features. Over 1,100 varieties of annual flowers were grown and evaluated during the 2001 season and a performance report was published and sent to all cooperators and industry personnel. As a result of these trials, New Guinea Impatiens and vegetatively propagated Verbena's have become a more important flower crop to the state. Seven plant species were recommended or introduced to the trade and public by Plant Select in 2001. Over 450,000 of the 2001 Plant Select plants were tagged or sold in 2001. In 2002, seven plants are being recommended or introduced. New and standard herbicides, Oxyfluorfen and pendimethalin, benefin and trifluralin, oxadiazon, oxyfluorfen and oryzalin and pendimethalin were evaluated for their weed control effectiveness and phytotoxic effect on six genera of container-grown herbaceous perennials and woody plants at two sites in Colorado. All herbicides tested controlled weeds well with no major phytotoxicity. A multi-year study was started in 2001 at two sites in Colorado to study the feasibility of pot-in-pot production system for caliber tree production. Initial data after one growing season shows some increased growth from this system with additional fertilizer and water treatments. Another cooperative multi-year study was initiated in 2001 to determine the importance of mycorrhizae treatments to newly transplanted and established trees in the landscape. Initial results after one growing season has not resulted in any significant increase in growth due to various mycorrhizal treatments. |
| 2002 | Woody and herbaceous plants continue to be evaluated for adaptability to High Plains on a 22 ha site. Woody (70 taxa) and herbaceous plants (30 taxa) were acquired in 2002 for evaluation. Performance records for 3,212 taxa of woody and herbaceous plants were entered into a computer system. Over 1,165 varieties of annual flowers were grown and evaluated during the 2002 season and a performance report was published and sent to all cooperators and industry personnel. As a result of these trials, New Guinea Impatiens and vegetatively propagated petunias, verbena's and dahlia's have become more important flower crops in the state. Seven plant species were recommended or introduced to the trade and public by Plant Select in 2002. In 2003, seven plants are being recommended or introduced. In 2002, a multi-site woody plant trial was initiated to evaluate long term (5 years) future woody Plant Select introductions. Twelve taxa were planted at all sites. New and standard herbicides, prodiamine, trifluran, flumioxazin, isoxaben and pendimethalin were evaluated for their weed control effectiveness and phytotoxic effect on four genera of container-grown herbaceous perennials at two sites in Colorado. All herbicides tested controlled weeds well with no major phytotoxicity. In 2002, a drought and heat tolerance study with Oenothera macrocarpa ssp. Incana Silver Blade was initiated. This plant can survive and flower in dry soils. Continuous blooming in drought is credited to style abscission versus flower abscission. The multi-year feasibility study for pot-in-pot production for caliper trees continued at 2 sites. Plants at the Grand Junction site were approximately three times the size of the plants grown at the Front Range site. This is attributed to longer growing season when adequate moisture is applied. However soil temperatures remained similar between above and below ground pots throughout the year. |
| 2003 | Woody and herbaceous plants continue to be evaluated for adaptability to the High Plains on a 25 ha site. Woody (85 taxa) and herbaceous plants (74 taxa) were acquired in 2003 for evaluation. Performance records for 2800 taxa of woody and herbaceous plants were entered into a computer system which is available on a website. Over 950 varieties of annual flowers were grown and evaluated in 2003 and a performance report was published and sent to all cooperators and industry personnel in the state and region. New Guinea impatiens, angelonia, vegetatively propagated petunias and verbenas have become a more important bedding plant crop in the state. Seven plant species were recommended or introduced to the trade and public by Plant Select (TM) in 2003. In 2004 seven additional plants are being recommended or introduced. In 2003 over 900,000 Plant Select (TM) plant labels were sold which is the best estimate of the number of Plant Select (TM) plants sold in 2003. The multi-site woody plant trial continued with the planting of an additional eight taxa at five locations throughout the state. A new herbicide:flumioxazin (Broadstar) was evaluated for weed control effectiveness and phytotoxic effect on twelve genera of container grown landscape plants at two sites in Colorado. Most herbicides tested controlled weeds well with phytotoxicity observed only on Cerastium tomentosum, Achillea millifolium, Hydrangea arborescens, and Lonicera tatarica at two and four times the recommended rate. Phenotypic plasticity of Oenothera macrocarpa ssp.incana response to heat, water and light stress was studied. Only minor variations were observed in plant form in response to water and heat stress. However, a phenomenon termed partial style abscission (PSA) occurred from late June until early October. PSA occurred more frequently with increasing daily temperatures and contributed to limiting seed set with 0. macrocarpa ssp. incana. Preliminary lysimeter research was initiated in 2003 to determine daily water use of Acer x freemanii 'Jeffersred'-Autumn Blaze(TM) maple during cycles of decreasing soil moisture . Future lysimeter research will focus on root development and water use. |
| 2004 | Woody and herbaceous plants continue to be evaluated for adaptability to the High Plains on a 25 ha site. Woody (76 taxa) and herbaceous plants (140 taxa) were acquired in 2004 for evaluation. Performance records for 2850 taxa of woody and herbaceous plants were entered into a computer system, which are available on two websites. Close to 1,000 varieties of annual flowers were grown and evaluated in 2004 and a performance report was published and sent to all cooperators and industry personnel in the state and region. Many vegetatively propagated annual varieties, including petunias, verbenas and New Guinea impatiens have become important bedding plant crops in the state, due to this research. Seven plant species were recommended or introduced to the trade and public by Plant Select in 2004. In 2005, seven additional plants are being recommended or introduced. In 2004, close to one million Plant Select plant labels were sold which is the best estimate of the number of Plant Select plants sold. The multi-site woody plant trial continued with the planting of an additional five taxa at five locations throughout the state. A new herbicide, Pendimethalin (Pendulum 2G) was evaluated for weed control effectiveness and phytotoxic effect on twelve genera of container grown landscape plants at two sites in Colorado. The herbicide showed no phytotoxicity at either site. Pendimethalin controlled between seventy to ninety-five percent of six genera of weeds sown initially in the containers. Research continued with Acer x freemanii Autumn Blaze the second growing season to determine if container grown transplanted trees will initially grow more than ball and burlapped transplanted trees. Also, we hoped to determine if trees grown a second year in a pot-in-pot system would achieve increased growth when transplanted into larger containers. When Autumn Blaze (TM) maples are planted according to national guidelines, pot-in-pot container grown trees generated greater trunk and shoot growth than balled and burlapped transplanted trees during their first growing season after transplanting. One reason for this result was the greater amount of intact roots from the container grown trees versus balled and burlapped trees resulting in less water stress in the young trees. No significant differences in trunk or shoot growth were observed when pot-in-pot grown trees were transplanted to larger pot-in-pot containers versus staying in smaller pot-in-pot container after one growing season. |
| 2005 | Woody and herbaceous plants continue to be evaluated for adaptability to the High Plains on a 30 ha site. Woody (55 taxa) and herbaceous plants (160 taxa) were acquired in 2005 for evaluation. Performance records for 2975 taxa of woody and herbaceous plants were entered into a computer system, which is available on three websites. Over 1,150 varieties of annual flowers were grown and evaluated in 2005 and a performance report was published and sent to all cooperators and industry personnel in the state and region. Many vegetatively propagated annual varieties, including petunias, calibrachoa, verbenas, osteospermums and New Guinea impatiens have become important bedding plant crops in the state, due to this research. In 2005, seven plant species were recommended or introduced by Plant Select. In 2006, eight additional plants are being recommended or introduced. In 2005, over 1.3 million Plant Select plant labels were sold which is our best estimate of the number of Plant Select plants sold. Over fifty-five demonstration gardens are displaying Plant Select plants throughout Colorado. The multi-site woody plant trial continued at five locations throughout the site along with a cold hardiness study conducted with Cupressus arizonica at three of the sites. Three herbicides: Pendulum 2G (pendimethalin), Pennant Magnum 26EC (s-metolachlor) and Snapshot 2 .5+G (isoxabem + trifuratin) were evaluated for weed control effectiveness and phytotoxic effect on four genera of herbaceous plants at two sites in Colorado. Pennant Magnum 7.26EC resulted in severe phytotoxicity and stunted growth at most rates on all four taxa. Snapshot 2.5+G at recommended rate resulted in no phytotoxicities or stunted growth. The safest herbicide applied was Pendulum 2G which resulted in no phytoxicity and good weed control. In 2005 research began on determining water requirements of eight landscape shrubs and two species of turf grass. The 2005 season was used to design the research area, install the irrigation system and plants and various data collection techniques. The pot-in-pot method is being used to gravimetrically determine plant water loss. Baseline data was acquired in 2005 in this study and a drought tolerance study with plants being subjected to four different amounts of supplemental irrigation (100%, 50%, 25% and 0% of ET) was established. Research continues on determining water use in a multi-canopy urban landscape with Fraxinus pennsylvanica. The plots are exposed to varying levels of irrigation and are monitored to measure soil water depletion. Stem flow gauges are being used to measure water uptake. Stomatal conductance, water potential and leaf temperatures are being measured in the trees in various plots. |
| 2006 | Woody and herbaceous plants continue to be evaluated for adaptability to the High Plains on a 30 ha site. Woody (53 taxa) and herbaceous plants (22 taxa) were acquired in 2006 for evaluation. Performance records for 2950 taxa of woody and herbaceous plants were entered into a computer system, which are available on three websites. Over 1,300 varieties of annual flowers were grown and evaluated in 2006 and a performance report was published and sent to all cooperators and industry personnel in the state and region. Many vegetatively propagated annual varieties, including argyranthemum, calibrachoa, coleus, New Guinea impatiens, osteospermum, petunia and verbena have become important bedding plant crops in the state, due to this research. In 2006, eight plant species were recommended or introduced by Plant Select . In 2006, over 1.7 million Plant Select plant labels were sold which is our best estimate of the number of Plant Select plants sold. Over seventy-five demonstration gardens are displaying Plant Select plants throughout Colorado. The multi-site woody plant trial continued at five locations throughout the state with the additional planting of seven taxa in spring of 2006. Plants tested for five years are being extensively evaluated and Cupressus arizonica from the 2002 planting will be a future Plant Select recommendation. In 2007, seven additional plants are being recommended or introduced. Three herbicides: sulfentrazone, halosulfron and experimental V-10142 were evaluated for weed control effectiveness and phytotoxicity on four herbaceous plants with the experiment starting at three different times in Fort Collins. Sulfentrazone, halosulfron, and V-10142 resulted in phytotoxicity and reduced dry weights on three of four plant species evaluated. The 2006 season was a very dry season in Fort Collins which yielded exceptional data on the water use study of landscape shrubs and turfgrass. In the lysimeter study, plant water use at full saturation by plant area shows that Kentucky bluegrass uses about 65% of reference ETo. Bluemist spirea used about 60% of reference ETo. Both common lilac and three-leaf sumac used less water than Kentucky bluegrass. In the drought tolerance study, visual ratings showed tall fescue and Kentucky bluegrass were the only plant species to show physiological stress due to water. Depth of rooting is a common drought avoidance mechanism. This is one major difference between shrub and grass species. More extensive rooting systems result in more water available to plants. Irrigation in the landscape should focus less on individual plant's water use and more on maintaining adequate soil moisture in plant rooting zone. |
| Impact | |
| 1999 | Production & sales of New Guinea impatiens in Colorado has grown tremendously due to favorable trials at Colorado State. Plant Select plants are now readily available in most garden centers in Colorado, allowing consumers to plant hardier & more adaptable landscape plants. By the spring of 2000, over 2,000,000 plants will have been sold since its inception in 1997. Nursery producers & retailers are storing balled & burlapped woody plants with stretch wrap around the balls since it was found to help reduce transplant shock with woody plants. |
| 2000 | Bedding plant growers & consumers throughout Colorado & the region look to Colorado State for evaluation of both seed and asexually propagated bedding plant varieties. Production & sales of New Guinea impatiens, asexually propagated verbena, petunia and angelonia have grown tremendously due to favorable trials at Colorado State. Plant Select plants are now being grown and observed in gardens throughout Colorado and are available in most garden centers. These plants are hardier & more adaptable to Colorado climatic conditions. More than 175,00 Plant Select plants were tagged and sold in 2000. Nursery producers are utilizing numerous herbicides tested in our research plots for container grown herbaceous perennials with little phytotoxicity and good weed control saving producers dollars and labor. |
| 2001 | Bedding plant growers and consumers throughout Colorado and the region look to Colorado State for evaluation of both seed and asexually propagated bedding plant varieties. In 2001, with the partial move of the trials to a new site has increased visibility and impact of the trials to industry and public. Production and sales of New Guinea impatiens, geraniums and asexually propagated verbena and petunia continue to grow, due to favorable trials at Colorado State. Plant Select plants are being grown and displayed in numerous (20+) gardens throughout Colorado and the region and are displayed prominently in most garden centers. More than 450 ,000 Plant Select plants were tagged and sold in 2001. Nursery and herbaceous plant growers are utilizing numerous herbicides tested in our research plots for container production with little phytotoxicity and good weed control, saving producers dollars and labor. |
| 2002 | Bedding plant growers and consumers throughout Colorado and the region look to Colorado State for evaluation of both seed and asexually propagated bedding plant varieties. In 2002, with more of the trials moved to a new site including container trials has increased visibility and impact of the trials to industry and public. Production and sales of New Guinea impatiens, asexually propagated verbena's, petunias and dahlia's, continue to increase due to favorable trials at Colorado State. Plant Select plants are being grown and displayed in numerous (25+) gardens throughout Colorado and the region and are displayed prominently in most garden centers. More than 510,000 Plant Select plants were tagged and sold in 2002. Herbaceous perennial growers are utilizing herbicides tested in our research plots for container production with little phytotoxicity and good weed control, saving producers dollars and labor . |
| 2003 | Improper selection of landscape plant material can result in financial loss and dissatisfaction to homeowners and industry personnel. Introduction and evaluation of adaptable landscape plant material will identify proper plant material. Container production of landscape plants continues to offer a challenge to Colorado growers. Research will continue to define safe and effective herbicides and other modified container production techniques so growers will be successful. Daily water use of container nursery crops needs to be known to help in drought years. Research will continue to determine water use for maximum growth. |
| 2004 | Specific performance results from annual flower trials will help determine which new and superior annual varieties growers throughout state and region will grow and market. These superior annuals will be available to consumers who ultimately will have more success in gardening. Plant Select plants promoted throughout region and country mean more profitable plants to growers and ultimately gardeners. Weed control research helps growers control weeds in container production, which ultimately lowers the overall cost of production, which is often passed on to consumers. |
| 2005 | Specific performance results from annual flower trials will help determine which new and superior annual varieties growers throughout state and region will grow and market. These superior annuals will be available to consumers who ultimately will be more successful in gardening. Plant Select plants which are introduced or recommended throughout the state and region means marketing more profitable plants for growers in the region. Weed control research helps growers control weeds in container production, which ultimately lowers the overall cost of production, which is often passed on to consumers. Exact water requirements of shrub species will help all property managers and homeowners ultimately conserve water use in landscapes. |
| 2006 | Specific performance results from annual flower trials will help determine which new and superior annual flower varieties growers throughout state and region will grow and market. These superior annuals will become available to consumers who ultimately will be more successful in gardening. Plant Select plants which are introduced or recommended throughout the state and region mean marketing more profitable plants for growers in the state and region . Weed control research helps growers control weeds in container production, which ultimately lowers overall cost of production, which is often passed on to consumers. Water requirements of shrub and turf species will help all property managers and homeowners ultimately conserve water use in landscapes. |
| Publications | |
| 1993 |
FAIRCHILD, D.H. & KLETT, J.E. 1993. Woody Landscape Plants for the High Plains. Colo. State Univ. AES Tech. Bul. LTB 93-1. 109 p. FAIRCHILD, D.H. & KLETT, J.E. 1993. Woody Plants Worth Considering For Colorado Landscapes. Colo. Green 8(4):6-8. KLETT, J. E. 1993. Crabapple Evaluation Studies in Colorado. MALUS 7(2):15-17. KLETT, J. E. 1993. More Unusual Trees for Colorado. Colo. For. Assn. Nwsl. 11(6):6-8. REEVES, S. G. 1993. Napropamide Leaching in Container Nursery Media. M. S. Thesis. Colo. State Univ. Fort Collins, 83 p. REEVES, S.C. & KLETT, J.E. 1993. Reducing Herbicide Leaching in Containerized Nursery Stock. Colo. Green 9(1):15. STAATS, D & KLETT, J.E. 1993. Putting Water Needs To The Test. Colo. Green 9(2):6-7. STAATS, D. & KLETT, J.E. 1993. Evaluation of Weed Control and Phytotoxicity of Preemergence Herbicides Applied to Container-Grown Herbaceous and Woody Plants. J. Envir. Hort. 11(2):78-80 . STAATS, D. & KLETT, J.E. 1993. Water Conservation Potential of Non-Turf Ground Covers versus Kentucky Bluegrass Under Increasing Levels of Drought Stress. HortScience 28(5):536. (Abstr.). STAATS, D. P. 1993. Evaluation of Quality & Water Conservation Potential of Non-Turf Groundcovers vs. Kentucky Bluegrass. M.S. Thesis Colo. State Univ., Fort Collins. 126 p. |
| 1994 |
KLETT, J. E. 1994. Annual Flower Trials: What's New for 1994. Colo. Green 10(1):30-31. KLETT, J. E. 1994. Application Rate Studies of Non-Turf Groundcovers. Colo. Green 10(2):24-25. KLETT, J. E. 1994. Maple and Ash Tree Species Worth Considering for Colorado. Colo. Green. 9(4):26-27. KLETT, J. E. 1994. Ornamental Grasses for Landscape Use. Colo. Green 10(3):28-29. KLETT, J. E., STAATS, D. & HILLOCK, D. 1994. Preemergent Weed Control in Container-Grown Herbaceous Perennials. HortScience 29(5):555 (Abstr.) STAATS, D. & KLETT, J. E. 1994. Water Conservation of Non-Turf Ground Covers vs. Kentucky Bluegrass. American Nurseryman. 180(8):85-87. STAATS, D. & KLETT, J. E. 1994. Water Use of Kentucky Bluegrass and Ground Covers. HORTIDEAS 11(12):142. |
| 1995 |
COX, R.A. and KLETT, J.E. 1995. Evergreen Trees for Colorado Landscapes. Service in Action No. 7.403 D. HILLOCK and KLETT, J.E. 1995. Evaluation of Four Herbaceous Perennials Under Increasing Levels of Drought Stress. HortScience 30(4):798 (Abstr.) KLETT, J.E. 1995. Container Media Research. Colo. Green 11(1):38-39 KLETT, J.E. 1995. Crabapples in Colorado. Colo. Green 10(4):34-36 KLETT, J.E. 1995. Superior Landscape Trees for Colorado. Colo. Green. 11(2):24-26 KLETT, J.E. 1995. Under-used Dwarf Shrubs Adaptable for Colorado. Colo. Green 11(2):30-31 KLETT, J.E. 1995. Winter 1995 Colorado State University Research Update - Crabapple Evaluation Studies in Colorado. Colo. Forestry Assoc. newsletter 14(3):12-14 KLETT, J.E. and COX, R.A. 1995. Rock Garden Plants. Gardening Series. No. 7.401 3p KLETT, J.E. and HILLOCK, D. 1995. Preemergent Weed Controlin Container-grown Herbaceous Perennials. HortScience 30(4):819 (Abstr.) KLETT, J.E. and SLUMP, K. 1995. Plant Select for the Rocky Mountains and Plains States. Landscape Plant News 6(3):14-15 STAATS, D. and KLETT, J.E. 1995. Water Conservation Potential and Quality of Non-Turf Ground Covers vs. Kentucky Blue Grass Under Increasing Levels of Drought Stress. J. Environ.Hort. 13(4):181-185 TOLAN, R.J. and KLETT, J.E. 1995. Growth Comparison of Trees Produced Under Three Production Methods and Two Irrigation Treatments. HortScience 30(4):794 (Abstr.) |
| 1996 |
HILLOCK, D. A. 1996. Herbaceous Perennials & their Performance Under Increasing Levels of Drought Stress. M.S. Thesis. Colo. State Univ. Ft Collins 102p. HUGHES, H. G. & KLETT, J.E. 1996. Accommodating Change in a Diverse Horticulture Curriculum. HortScience 31(4):694 (Abstr.) KLETT, J. & COX, R. 1996. Ground Cover Plants. Gardening Series. No. 7.400 4p. Colo. State Univ. Coop Ext Ser KLETT, J. E. 1996. 1997 Plant Select: Colorado's Best. NM Pro.16(10)16. KLETT, J. E. 1996. Annual Flower Trials - What's New for 1996. Colo. Green 12(1):34-35. KLETT, J. E. 1996. Crataegus: Hawthorn. Colo. Forestry Assoc. Newsletter 15(5):12-14. KLETT, J. E. 1996. Observations on Woody Plant Stress. Colo. Green 12(3):42-43. KLETT, J. E. 1996. Plant Select for the Rocky Mountains and Plains States. Colo. Green 12(2):34-35. KLETT, J. E., HILLOCK, D. & STAATS, D. 1996. Preemergent Weed Control in Container-grown Herbaceous Perennials. HortScience. 31(4):660 (Abstr.) KLETT, J.E. & COX, R.A. 1996. Wildflowers in Colorado. Gardening Series. No. 7.233 4p. Colo. State Univ. Coop Ext Ser. MEEHAN, M., KLETT, J.E. & COX, R.A. 1996. Herbaceous Perennials. Gardening Series. No. 7.405 4p. Colo. State Univ. Coop Ext Ser TOLAN, R. & KLETT, J. E. 1996. Review of 1995 Growing Season. Colo. Green 11(4):30-31. TOLAN, R. J. 1996. Fabric Containers Versus Traditional Tree Production Methods:a Post Transplant Study. M.S. Thesis. Colo. State Univ. Ft Collins 84p. |
| 1997 |
COX, R. A. and KLETT, J. E. 1997. Deciduous Shrubs for Colorado. Colo. State Univ. Coop Ext .Gardening Series. No. 7.415 4 p DUNN, S. , STAATS, D. and KLETT, J. E. 1997. Preemergent Weed Control in Container- grown Herbaceous Perennials. HortScience. 32(3):010 (Abstr. DUNN, S. W. and KLETT, J. E. 1997. Growth After Mechanical Root Pruning of Herbaceous Perennials Under Increasing Levels of Water Stress. HortScience 32(3)684. (Abstr. HILLOCK, D. A. and KLETT, J. E. 1997. Herbaceous Perennials and Drought Stress. Colo. Green 13(2):342 KLETT, J. E. 1997. New Plants for 1998. American Nurseryman 186(12):64,68,74 KLETT, J. E. 1997. Ornamental Grasses for Colorado. Colo. Green 13(4):28-29 KLETT, J. E. 1997. Superior Herbaceous Perennials. Colo. Green 13(3):34-35 KLETT, J. E. 1997. The Best, New Annuals for 1997. Colo. Green 13(1):38-39 KLETT, J. E., BOYLE, D., COX, R. A., WILSON, C., and POTTORFF, L. 1997. Colo. State Univ. Coop . Ext. XCD08 Lawn Problem Solver CD-Rom. WALDO, A. J. and KLETT, J. E. 1997. The Effects of Three Nursery Production Methods on Tree Growth Rate. HortScience 32(3):681 (Abstr. |
| 1998 |
DUNN, S. 1998. Growth After Mechanical Root Pruning of Container-grown Perennials Under Increasing Levels of Water Stress. M.S. Thesis 130 p DUNN, S. and KLETT, J.E. 1998. Herbaceous Perennials in Drought. Colo. Green 14(4):36-37 DUNN, S., KLETT, J. E. and STAATS, D. 1998. Preemergent Weed Control in Container-grown Herbaceous Perennials. HortScience. 33(3):229 (Abstr. KLETT, J. E. 1998. Much Ado about Mulches. Colo. Green 14(3):10-12,25 KLETT, J. E. 1998. New Plants for 1999. American Nurseryman 188(12):50,51,63,64,74,7 KLETT, J. E. 1998. The Best New Annuals for 1998. Colo. Green 14(2):38-39 KLETT, J.E. 1998. Celtis occidentalis - Common Hackberry. Colorado Forestry Association Newsletter 17(6):6 KLETT, J.E. 1998. Ongoing Research from CSU. Colo. Green 14(3)36-37 KLETT, J.E. 1998. Xeric Annuals and Perennials. Colo. Green 14(1):40-41 STAATS, D., HILLOCK, D., and KLETT, J.E. 1998. Weed Control and Phytotoxicity of Preemergence Herbicides Applied to Container-grown Herbaceous Plants. Hort Technology 8(3)325-328 |
| 1999 |
GRUBB, BRIAN 1999. Post-Harvest Storage and Establishment of Balled and Burlapped Tilia cordata Mill `Greenspire' M.S. Thesis. 64 p KLETT, J. E. 1999. Best Annuals for 1999. Colo. Green 15(1):44-45 KLETT, J. E. 1999. New Plants for 2000. American Nurseryman. 190(12)35, 62, 70 KLETT, J. E. 1999. Root-Pruned perennials and Water Stress. Colo. Green 15(4):38-39 KLETT, J. E. and Brian Grubb. 1999. Potting Media for Container-Grown Annuals. Colo. Green 15(3):32-33 KLETT, J.E. 1999. 1999 Annual Trial Garden Performance Report. 107 p KLETT, J.E. 1999. Annuals for the New Millennium. Colo. Green 16(1)38-41 KLETT, J.E. 1999. Planttalk Colorado. Colorado Forestry Association. 18(4)1 KLETT, J.E. 1999. Under-Used Woody Plants for Colorado. Colo. Green 15(3):32-33 KLETT, JAMES E., Laurel Potts and David Staats. 1999. Preemergent Weed Control in Container-Grown Herbaceous Perennials. HortScience. 34(3)444 SCOTT, KIRSTEN. 1999. Enhancing Germination of Fraxinus anomala. M.S. Thesis 64 p |
| 2000 |
Klett, J. E. 2000. Annuals for the new millennium. Colo. Green. 16(1):38-41. Klett, J. E. 2000. Flowering crabapples as ornamental trees. Colo. Green 16(4):35-37. Klett, J. E. 2000. Woody Plants worth considering in 2000. Colo. Green 16(2): 34-37. Klett, J. E. and M. Boyles 2000. Colorado State University 2000 Annual Flower Trial Garden Report. 171 p. (unpub) Klett, J. E., and D. Staats. 2000. Preemergent Weed Control in Container-Grown Herbaceous Perennials. HortScience. 35(3):221(abstr). Klett, J.E and M. Boyles. 2000. Summer's best - University trials - Colorado State. Greenhouse Grower 18(12): 94, 96, 98. Klett, J.E. 2000. New Plants for 2001. Amer. Nurseryman 912(12):40, 52. Klett, J.E. 2000. Ornamental grasses from Colorado State's research trials. Colo. Green 16(3):34-35. Oakley, D., J. Laufman, J. Klett, and H. Hughes. 2000. Overcoming seed dormancy in winecups, Callirhoe involucrata. HortScience 35(3):450 (abstr.). Waltman, D., J. E. Klett and R. A. Cox. 2000. Perennial gardening. Colorado State Univ. Coop. Ext. Gardening Series. No. 7.402 |
| 2001 |
Boyles, M. and J.E. Klett. 2001. Superior Annuals from 2000 Trials. Colo. Green. 17(1):35-38. Klett, J.E. 2001 Research Think Tank Held. CNA Looseleaf 18(4):6. Klett, J.E. 2001. 2001 Annual Flower Garden Trials. CNA Looseleaf. 18(5):6. Klett, J.E. 2001. Fertilizer for Container-Grown Annuals. Colo. Green. 17(2):30-37. Klett, J.E. 2001. Outstanding in the Field. Growers Talk 65(6):38-42. Klett, J.E. 2001. Plant Select Woody Plant Selections for 2001 and 2002. CNA Looseleaf 18(3):12-13. Klett, J.E. 2001. Plenty O'Plants. Amer. Nurseryman 194(12):36, 62, 63, 68. Klett, J.E. 2001. Promising Woody Plants for 2002. Colo. Green. 17(4):37-38. Klett, J.E. 2001. Proven Herbaceous Perennials. Colo. Green. 17(3):20-25. Klett, J.E. 2001. Summer's Best. Greenhouse Grower. 19(12):44-45. Klett, J.E. and C. Sikora. 2001. Colorado State University 2001 Annual Trial Garden Performance Report. 178 p. (Unpubl.) Klett, J.E., H. McMillan and S. Eubank. 2001. Planttalk Colorado . HortScience 36(3):478 (abstr.) Staats, D. and J. Klett. 2001. Preemergence Weed Control in Container-Grown Herbaceous Perennials. HortScience 36(3):500 (abstr.) |
| 2002 |
Cummins, A., Klett, J. and Rogoyski, M. 2002. Tree production utilizing Pot-in-Pot techniques. XXVI International Horticultural Congress. Toronto, Ontario. P. 464 (abstr). Klett, J.E. 2002. 2002 Bedding plant trials. Greenhouse Product News. 12(13):30. Klett, J.E. 2002. Adaptability evaluation continues. CNA looseleaf 19(4):16. Klett, J.E. 2002. Field mycorrhizae research. CNA looseleaf 19(2):6. Klett, J.E. 2002. Field tested and approved. Grower Talks. 66(7):84. Klett, J.E. 2002. Flower garden trials. CNA looseleaf 19(5):8-9. Klett, J.E. 2002. Increasing tree quality in pot-in-pot (PIP) grown nursery stock. CNA looseleaf 19(1):6-7. Klett, J.E. 2002. Passing the test. Greenhouse Grower. 20(12):38-42. Klett, J.E. 2002. Plant Select Xeriscape demonstration gardens. Colo. Green 18(4):31. Klett, J.E. 2002. Superior Acer, Prunus, and Cotinus. Colo. Green 18(2):44. Klett, J.E. 2002. Superior annuals. Colo. Green 18(1):31-33. Klett, J.E. 2002. Superior herbaceous perennials. Colo. Green 18(3):31. Klett, J.E. 2002. Thoughts from second think tank meeting. CNA looseleaf 19(3):9. Klett, J.E. and Monroe, P. J. 2002. Colorado State University 2002 Annual trial garden performance report. 134 p. (unpublished). Klett, J.E., Fahey, B., and Cox, R. 2002. Native shrubs for Colorado landscapes. Colo. State Univ. Coop. Ext. Gardening Series. No. 7.422. Klett, J.E., Fahey, B., and Cox, R. 2002. Native trees for Colorado landscapes. Colo. State Univ. Coop. Ext. Gardening Series. No. 7.421. Staats, D. and Klett, J. 2002. Pre-emergence weed control in container-grown herbaceous perennials. XXVI International Horticultural Congress. Toronto, Ontario. P. 615 (abstr). Tannehill, C. and Klett, J.E. 2002. Best perennials for the Rocky Mountain and high plains. Colo. State Univ. Coop. Ext. Bul 573A. 128p. |
| 2003 |
Cummins, A. 2003 Tree production utilizing Pot-in-POt Techniques. M.S. Thesis. Department of Horticulture & Landscape Architecture. Colo State Univ. Fort Collins, CO 73pgs. Klett, J. and Badertscher, K. 2003. Planttalk Colorado. HortScience. 38(5):731 (abstract) Klett, J. and Cummins, A. 2003. Tree Production Utilizing Pot-In-Pot Techniques. CNA Loosleaf. 20(4):15. Klett, J. and Mobley, R. 2003. Colo. State Univ. 2003 Annual Trial Garden Performance Report. 86 p. (Unpublished) Klett, J. E. 2003. 2003 Annual Flower Trial Report. CNA Looseleaf. 20(6):9. Klett, J. E. 2003. 2003 Bedding Plant Trials. Greenhouse Product News. 13(13):20. Klett, J. E. 2003. Best Perennials for Rocky Mountain and High Plains. CNA Looseleaf. 20(2):7 Klett, J. E. 2003. Dispatches from the Field. Growers Talk. 67(6):37. Klett, J. E. 2003. Drought and Heat Tolerance of Herbaceous Perennials. ColoGreen. 19(3):31. Klett, J. E. 2003. Field Trial Fanfare. GM Pro. 23(10):31. Klett, J. E. 2003. Flowers for Color in Drought. ColoGreen 19(1):37. Klett, J. E. 2003. Home Landscape Watering During Drought. Colo. State Univ. Coop. Ext. Gardening Series No. 7.240. Klett, J. E. 2003. New Trees Evaluated. ColoGreen 19(4):34. Klett, J. E. 2003. Plant Select CNA Looseleaf. 20(1):11-12 Klett, J. E. 2003. Summer's Best. Greenhouse Grower. 21(12):60-61. Klett, J. E. 2003. Superior Annuals from 2003 Trials. ColoGreen 19(2):32 Klett, J. E. 2003. Woody Plant Evaluation Report. CNA Looseleaf. 20(5):17-19. Klett, J. E. 2003. Woody Plant Trial Performance Report. CNA Loosleaf. 20(3):8. Klett, J., Staats, D. and Rogoyski, M.. 2003. Pre-emergence Weed Control in Container-grown Herbaceous Perennials and Woody Plants. HortScience 38(5):700 (abstract) Litus, G. and Klett, J. 2003. Partial Style Abscission in Oenothera macrocarpa spp. incana. HortScience 38(5): 776 (abstract) |
| 2004 |
Klett, J.E. 2004. Bedding Plant Trials. Greenhouse Product News 14(13):26. Klett, J.E. 2004. Best in the Field. Grower Talks 68 (6):40-41. Klett, J.E. 2004. Plant Select Woody Plants. ColoGreen 20 (2):50-51. Klett, J.E. 2004. Research Update. Looseleaf 21 (1):13. Klett, J.E. 2004. Superior Annuals from 2003 Trials. ColoGreen 20 (1):51-52. Klett, J.E. 2004. Superior Annuals from 2004 Trials. Looseleaf 21 (6):7. Klett, J.E. 2004. Superior Herbaceous Perennials. ColoGreen 20 (4):50-52. Klett, J.E. 2004. Thoughts from Think Tank Meeting. Looseleaf 21 (3):7-8. Klett, J.E. 2004. Tried and True. Greenhouse Grower 22 (12):60. Klett, J.E. and Litus, G. 2004. Water Use in Autumn Blaze Maple. Looseleaf 21 (2):6. Klett, J.E. and Litus, G. 2004. Water Use Studies with Woody Plants. Looseleaf 21 (5):4-5. Klett, J.E. and MacDonald, R. 2004. Woody Plants. ColoGreen 20 (3):41-42. Klett, J.E., Cosenza, J. and Staats, D. 2004. Colorado State University 2004 Annual Trial Garden Performance Report. 95 p. (unpub.) Klett, J.E., Staats, D. and Rogoyski, M. 2004. Preemergence Weed Control in Container Grown Herbaceous Perennials. HortScience 39 (4):745-46. (abstract). Litus, G. 2004. The Effects of Water Limitation and Heat on Flower Production, Resource Allocation and Partial Style Abscission in Oenothera macrocarpa ssp. incana. M.S. Thesis. Department of Horticulture & Landscape Architecture. Colo State Univ. Fort Collins, CO 77 pgs. Shonle, I, Vickerman, L. and Klett, J.E. 2004. Native Herbaceous Perennials for Colorado Landscapes. Colorado State University Coop. Ext. Gardening Series No. 7.242 6 p. |
| 2005 |
Hughes, H., Mogen, E., Newman, S., Klett, J. and Koski, A. 2005. Outcome Assessment of Resident Instruction: The Colorado State University Experience. HortScience 40(4) 1045. (abstract) Cox, R.A. and Klett, J.E.. 2005. Evergreen Trees. Colorado State University Coop. Ext. Gardening Series No. 7.403. 4p. Klett, J. E. 2005. Planttalk Colorado. 24-Hour Answer for Gardeners. HortScience 40(4) 995. (Abstract) Klett, J. E. 2005. Superior Annuals. ColoGreen 21(1) 64. Klett, J.E, Copenhefer, C. and Staats, D. 2005. Colorado State University 2005 Annual Flower Trial Garden Performance Report . 95 p. (unpub.) Klett, J.E. 2005. 2005 Research Project. ColoGreen 21(3) 53-54. Klett, J.E. 2005. Colorado State University 2004-05 Winter Pansy Trials Performance Report. 28 p. (unpub.) Klett, J.E. 2005. Container vs B&B for Woody Plants. ColoGreen 21(2) 58-59. Klett, J.E. 2005. Container Weed Control Research. Looseleaf 22(6) 4. Klett, J.E. 2005. Current Nursery and Greenhouse Research Projects. Looseleaf 22(1) 5. Klett, J.E. 2005. Plant Select Update. Looseleaf 22(4) 19. Klett, J.E. 2005. Planttalk Colorado Keeps on Growing. ColoGreen 21(4) 53. Klett, J.E. 2005. Research Continues Evaluating Herbaceous Perennials Best Suited for Region. Looseleaf 22(2) 8, 14. Klett, J.E. 2005. Research Update, Thoughts from the Think Tank. Looseleaf 22(3)14. Klett, J.E. 2005. Standing Trial. Growers Talk 9(6) 64. Klett, J.E. 2005. Superior Annuals from 2005 Trials. Looseleaf 22(5) 9, 10. Klett, J.E. 2005. Trialing the New Varieties. Greenhouse Product News 15(13) 60. Klett, J.E. and Cox, R.A.. 2005. Rock Garden Plants. Colorado State University Coop. Ext. Gardening Series No. 7.401. 4p. Klett, J.E., Staats, D. and Rogoyski, M. 2005. Pre-emergence Weed Control in Container-grown Herbaceous Perennials. HortScience 40(4) 1024. (abstract) Litus, G. and Klett, J.E. 2005. Comparison of First and Second-Year Growth between Container-grown Autumn Blaze Maple Trees. HortScience 40(4) 1125. (Abstract) Qian, Y. L., Fu, J. M., Klett, J.E. and Newman, S.E. 2005. Effects of Long-Term Recycled Wastewater Irrigation on Visual Quality and Ion Concentrations of Ponderosa Pine. J. Environ. Hort. 23(4) 185-189. |
| 2006 |
Klett, J. E. 2006. Underused Woody Plants. Colo Green 22 (3) 61-62. Klett, J.E. 2006 Colorado State University 2005-06 Winter Pansy Trials Performance Report (unpubl.) Klett, J.E. 2006. Butterfly Bloom. 25 North, May/June 2005. p. 54. Klett, J.E. 2006. More Unusual Woody Plants from Research Plots. Looseleaf 23 (1) 18. Klett, J.E. 2006. Plant Select for 2007. Looseleaf 23 (4) 12-13. Klett, J.E. 2006. Proven Herbaceous Perennials. Colo Green 22 (4) 61-62. Klett, J.E. 2006. Superior Annuals from the 2006 Trials. Looseleaf 23 (6) 12-13. Klett, J.E. 2006. Superior Annuals. Colo Green 22 (1) 52-54. Klett, J.E. 2006. Unusual Woody Plants. Colo Green 22 (2) 61-62. Klett, J.E. and Cox, R.A. 2006. Evergreen Shrubs for the Home Grounds. Colorado State University Coop. Ext. Gardening Series. No. 7.414. 6 p. Klett, J.E. and MacDonald, R. 2006. Plant Select Woody Plant Trials. Colo Green 22 (5) 61-62. Klett, J.E., Copenhefer, C. and Staats, D. 2006. Colorado State University 2006 Annual Flower Trial Garden Performance Report 123 p. (unpubl.) Litus, G. and Klett, J.E. 2006. Drought Stress and Recovery in Green Ash. HortScience 41 (4) 1009 (Abstract. Ounsworth, M. and Klett, J.E. 2006. Drought Avoidance and Drought Tolerance. Looseleaf 23 (5) 12-13. Ounsworth, M. and Klett, J.E. 2006. Water Requirements of Landscape Shrubs and Turfgrass. Looseleaf 23 (2) 8. Staats, D., Klett, J., Howlett, T. and Rogoyski, M. 2006. Pre-emergence Weed Control in Container-grown Herbaceous Perennials. HortScience 41 (4) 1034 (Abstract) |