Plant Select is a cooperative program sponsored jointly by the Denver Botanic Garden and Colorado State University with the help of local growers and horticulturalists. The purpose of the program is to "seek out, identify, and distribute the very best plants for landscapes and gardens from the intermountain region to the high plains." In other words, they test thousands of varieties of plants on their ability to flourish in our harsh climate, and then put their stamp of approval on those that meet their strict standards.
'Denver Gold' Columbine
Plant Select tests both existing and new varieties of plants and seeks to promote worthy plants that are less well known to gardeners. Ever heard of 'Sunset' Hyssop, California Fuchsia ‘Orange Carpet,' or 'Denver Gold' Columbine? You can thank Plant Select for testing their durability and promoting these plants nationwide. They were all Plant Select choices (1997 2001, 2001 respectively) and have become increasingly popular since their selection. Even gardeners not in the mountain region have and will continue to benefit from the information Plant Select disseminates.
Some notable past recommendations by Plant Select
'Cheyenne' Mock Orange (Philadelphus lewisii)
This North American native forms an attractive shape in a variety of sites and soils. A selection from the USDA Field Station at Cheyenne, Wyoming, where the parent plant has formed a spectacular and carefree specimen. It has thrived over many decades there with no care. Cheyenne Mock Orange boasts intensely fragrant, 2-inch white blooms. It is promoted as a xeriscape shrub and can grow up to 6 feet wide by 7 feet tall in full sun. It is hardy in zones 3 to 9, up to 8000 feet (Recommended in 2001.)
Winecups (Callirhoe involucrata)
Winecups is a well known and adaptable Colorado native that was selected for recommendation in 1999. It will flourish with neglect or care, which makes it an exceptional choice for many spots in the garden.
'Pike's Peak Purple' Penstemon (Penstemon x mexicali)
'Pike's Peak Purple' Penstemon is a durable hybrid selected from crosses made by Bruce Meyers between Mexican and American wild penstemons. It boasts narrow, dark green leaves that form an attractive mound and thrive in dry, poor soil where few other plants will. 'Pike's Peak Purple' is hardy in zones 4b to 8, and up to 7000 feet. (Recommended in 1999)
'Tanager' Gazania (Gazania krebsiana)
Tanager Gazanias offer a bright, extremely drought tolerant option for perennial gardens. Hardy to zone 6, it will thrive in full sun and bloom constantly from early summer to late fall. (Recommended in 2003.)
Silver Sage (Salvia argentea)
Though Silver Sage is noted for its huge, silvery leaves, it also produces a show-stopping spray of white flowers in early summer. A reliable perennial in our dry climate, this outstanding plant flounders within two years in wet climates. It is hardy in zones 4 to 10 and up to 8000 feet. (Recommended in 1997.)
Silver Fountain Butterfly Bush (Buddleia alternifolia ‘Argentea')
Unlike most familiar species of butterfly bush, which die to the ground almost every year, this tough ornamental is from the high, cold plains of northwestern China. It is adaptable to conditions in Colorado, blooming from the first year and quickly forming an elegant, vase-shaped, small tree or large shrub. It grows to a height and width of 10 feet or more, and has silvery branches that bear clouds of deep blue-purple flowers in June. It is hardy to zone 4 to 8 and up to 8,000 feet. (Recommended in 1998.)
PINK CRYSTALS® Ruby Grass (Melinis nerviglumis)
In 1998, Plant Select introduced the annual grass 'Pink Crystals' Ruby Grass. For years it is has amazed visitors to the Denver Botanic Garden with its unique and airy plumes of pink flowers and seedheads. Since its recommendation by Plant Select, it has become more widely available across the Rocky Mountain Region and country. 'Pink Crystals' is a drought tolerant, heat loving grass that works great en masse or as an accent among a perennial garden.
A Few 2009 Introductions/Recommendations
Korean Feather Reed Grass (Stipa brachytricha)
An elegant clump-forming grass that offers a fine alternative to 'Karl Foerster' grass. With feathery summer flowers and attractive fall and winter presence, this grass suits a variety of sites and conditions. This stunning perennial can reach up to 3 1/2 feet tall and blooms in late summer to early fall. It is hardy in zones 4 to 9 and up to 8000 feet, making it an excellent plant for many different areas.
'Denver Daisy' Rudbeckia
With a striking dark eyed, long-rayed daisy, this beauty was hybridized by Benary from the Colorado native Black-Eyed Susan (Rudbeckia hirta). 'Denver Daisy' Rudbeckia is dedicated in commemoration to the 150th anniversary of the founding of Denver. It is hardy in zones 3 to 9, up to 9000 feet. It can grow up to 2 1/2 feet tall, and blooms all summer long.
LAVENDER ICETM Ice Plant
The flowers of this variety are bright lavender with a dark eye, this striking sport of Table Mountain® Ice Plant occurred at Perennial Favorites Nursery in Rye, Colorado. This perennial groundcover grows only 2 inches high and can spread up to 2 feet from each plant. It is hardy in zones 4 to 9, up to 7000 feet.
Silverheels Horehound (Marrubium rotundifolium)
This vigorous mat-forming groundcover thrives in many sites and soils. A native plant from Turkey, Silverheels Horehound spreads up to 3 feet and grows 2 to 4 inches tall. It will thrive in any quality soil and full sun. It is hardy in zones 4 to 9 up to 8000 feet.
Not just for Rocky Mountain Gardeners
If you have variable, unpredictable weather conditions in your neck of the woods, Plant Select is a great place to start when choosing plants for your garden. Even if you don't live in the Rocky Mountain region, Plant Select is a good resource for discovering new and interesting plants that can survive almost anything! You can find more information at Plant Select's website.
Special thanks to Pat Hayward, Executive Director of Plant Select!
All photo credits thanks to Plant Select, with the exception of Pike's Peak Purple Penstemon (Qcapen), Winecups (LeeB678) and the photo of Pink Crystals Ruby Grass at DBG (S. Talbert).