By Kathy Brown, Colorado Master GardenerSM, Colorado State University Cooperative Extension, Denver County
Dont fence me in.
Perennials, annuals, trees, and shrubs can all be used alone or in combinations to create a lovely living screen.
Start by studying your particular screening problem. Is it a large area or a very small area? Are you trying to hide something unsightly, trying for a little privacy, or looking for something to separate the "rooms" of your garden? What would you like to see when you look there? Would a succession of flowers throughout the growing season or greenery be most appropriate?
What are your climate limitations? Do you have low water requirements (xeriscape)? Shade? Hot sun? What are your desires? Fall and winter interest? Low maintenance and low cost? Make a sketch of the area to be screened, and make notes about your requirements and preferences for the project. Keep in mind that some screens may need to serve dual purposes, such as shade and windbreak, shade and screen, security and privacy, and so forth.
In Colorado, altitude and climate provide some limitations as compared to milder climates. But there are still an amazing number of plant options to consider that provide beautiful and easy care screening solutions.
If you have plenty of room to plant, consider a tiered or layered look. Use a small tree with a wide top habit such as crabapple in the back. Plant medium height bushes in front (viburnums, spireas) and annuals, bulbs or a low ground cover in front of the bushes. Another option is tall ornamental grasses in the back with lower grasses in front. Or how about evergreens such as taller pine or fir in the back, evergreen or deciduous shrubs in front of the trees, then low evergreens or flowers in front of the shrubs?
Evergreen plants provide continuous screening year-round. If you use deciduous trees and shrubs in layers, select plants with multiple or curly stems to provide screening as well as visual interest in the winter months. Or use evergreen and deciduous mixes.
For very large areas, trees are most practical. Some good selections for screening are maples, buckeyes, and birches, as well as oak and elm. Study the habits (shape and growing features) of these trees and decide which ones will best serve the area. Mixtures of trees and large shrubs such as Russian olive and lilacs often do very well together.
Smaller areas can be screened successfully with a variety of plants such as several rose and cinquefoil bushes, or two to three small trees or tall shrubs. Keep in mind that odd numbers of plants generally look better than even numbers.
One medium-size weeping tree such as willow can provide a lot of screening and privacy. Another idea is a trellis with vines or some nicely staked berry bushes such as raspberry and blackberry. Some low evergreen shrubs such as dwarf or slow growing pines and spruce are very suitable for screening.
Hedges make very effective screens as well as barriers. They can be grown at various heights, from very low to very high (over 15 feet). Although used as a barrier, hedges can also provide security if thickly grown and prickly or thorny.
Be aware that hedges usually require more maintenance than other types of screens. It might be a little harder to get them started and grown to the desired height. Pruning must then be done often to keep the proper shape. Some popular evergreen and semi-evergreen trees that can be used for hedges are hawthorn, juniper and arborvitae. Incense cedar, European hornbeam, English holly, and hemlock may be considered in more protected Zone 5 growing zones with better, more acid soils. If thickly planted, they can also provide windbreak.
If privacy is needed for a patio where there is no room to plant outside the patio area, a row of containers might work. Large containers can have trellises trained with vines such as clematis for extra height. Small trees that grow well in containers also can be used. But remember, container plants are more vulnerable to weather and need more watering than other plants. Some plants may even require being brought indoors for the winter.
For areas requiring tall screens but with little planting area, look into tall grasses or bamboo. Some tall shrubs such as serviceberry, viburnums, and lilac take up less space than trees and require little maintenance. Other shrubs like flowering quince and Harry Lauders walking stick provide interesting flowers and stems throughout the year. They grow to five feet or higher and hardy to USDA Zone 4 Foothills areas.
Some screening situations may require less height such as a divider between houses or screening from the street. In the 4-5 foot height range, try floribunda roses such as Betty Prior (vivid pink), or Simplicity (dark pink). English shrub roses like Bredon with buff yellow rosettes are repeat bloomers and very fragrant. Hardy shrub roses can be low care and vigorous growers. Thickly planted, roses can also serve as a barrier or security screen.
Another suitable deciduous shrub of lower height is spirea, which has arching branches and dainty leaves with white or pink flowers. One beautiful 6-foot variety is Spirea x Vanhouttei, with old-fashioned bridal wreath type branches that arch to the ground. It is hardy from Zones 3 to 8.
Some patience is required in starting screen plantings, but the time is worth it for the beautiful result. Plant screens are low cost as compared to fencing and other hardscape structures. Check with your local nursery for additional varieties that do well in your area. Whether you like flowers, evergreens, interesting color features for winter, or other characteristics, with a little planning and imagination you can achieve your vision
Photograph courtesy of Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010