
by Kathy
Roth
Colorado State University Extension Master
Gardener
Larimer County
August gardeners lament the passing of colorful June
and July gardens, but we can extend our garden season into autumn and now is
the time to start. “Fallscaping” is a term developed by authors
Nancy Ondra and Stephanie Cohen. Fruits, berries, showy seed heads and a rainbow
of foliage colors are available to us, in addition to flowers that bloom as
the season cools. A trick the authors share is to base flower beds on plantings
that offer a summer-into-fall bloom period, along with good foliage and architecture
that allow plants to look attractive even when not in bloom.
Think beyond fall-blooming asters, chrysanthemums and goldenrods! Tricks such
as late seed sowing, shearing, dead heading and succession planting can give
you additional ways to obtain autumn glory. Deadheading (keeping the faded flowers
picked off) make repeat bloomers out of many early summer-blooming classics.
If this technique is impractical for you, simply shear them back in midsummer
for the same effect. For a detailed list of perennials and their bloom periods,
consult CSU Extension Fact Sheets #7.242
- Native Herbaceous Perennials for Colorado Landscapes and #7.405
- Herbaceous Perennials, which can be found by visiting www.ext.colostate.edu.
Certain border plants are considered long-bloomers: winecups have purple-pink
blooms on trailing green stems; speedwell, blanket flower, pincushion flower,
gaura, daylilies and low growing verbenas also offer tireless bloom. Lobelias,
Russian sage and rose mallows are other dependable August bloomers. True fall
bloomers include some varieties of sedum, goldenrods, certain monkshoods and
anemones. Fall-blooming bulbs are often forgotten. Cannas, autumn crocus, hurricane
lily (red spider lily), Guernsey lily and cyclamens are a few who produce fall
interest and then go dormant in spring. Richard Rosenfeld’s book Autumn
Plants provides more ideas along with lovely photographs.
Don’t forget perennial leaf color as well. Balloon flower, daylilies,
coneflowers, monkshoods, Siberian iris, various sedums, hosta, Solomon’s
seals and certain ferns will reward you with handsome yellow foliage. Many crave
oranges and reds in autumn. Dramatic color accent can be achieved with carefully
chosen shrubs and trees. Fact Sheet #7.229
- Xeriscaping Trees and Shrubs lists xeric choices, while #7.421
- Native Trees for Colorado Landscapes and #7.422
- Native Shrubs for Colorado Landscapes offer lists of native shrubs and
trees—noted are those with good fall color.
Late season annuals also abound. Cosmos, Mexican sunflower, cannas and dahlias
give terrific autumn display. Late sowing techniques work well with California
poppies, coreopsis, flowering tobacco, four-o’clocks, marigolds, nasturtiums,
cleomes, sunflowers and zinnias. Container plants may have “bloomed themselves
out” by autumn, so consider replanting containers for autumn color. Our
Colorado sunshine is warm enough to keep the blooms coming; try it!
Don’t overlook late-flowering shrubs and trees. Deadheading your butterfly
bush, Rose-of-Sharon and certain roses and hydrangeas will reward you with autumn
color. Certain vines will also come into their prime this season; Sweet Autumn
clematis, Golden clematis, various honeysuckles, Virginia creeper (with burgundy
leaves) and even grapevines! The lists of natives that produce fall color include
sumacs, mountain mahogany, black chokecherry, mountain ninebark, creeping barberry
and golden currant. Native shrubs with lovely fall berries include netleaf hackberry,
snowberry, gooseberry and serviceberry. Wood’s roses red seed hips hold
through winter while its purplish stems do not die-back. “Fort Collins
Native Plants” is available on the city’s website. It lists the
plants along with their characteristics and value to wildlife: http://www.fcgov.com/naturalareas/pdf/nativepl.pdf
Showy seed heads can be achieved by not deadheading. Don’t hurry to cut
down blooming flowers and perform fall clean up. The birds will thank you and
you’ll be rewarded with the awesome sight of plants coated by the first
snowfall. Grasses can be also be stunning this time of year. “Warm season
grasses” seed at the end of summer and should be considered for winter
interest. “Cool season grasses” hold their stems and plumes well
into fall. Consult Fact
Sheet #7.232 - Ornamental Grasses for descriptions and pictures.
The authors have received training through Colorado State University Extension's Master Gardener program and is a Master Gardener volunteer for Larimer County.
Gardening and Insect Fact Sheets are available on-line by clicking HERE.
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