In 1999, Plant Select® cooperators chose eight outstanding new plants for Rocky Mountain gardens. Plants include shrubs, groundcovers, an annual, a foliage plant and even a native aquatic grass.
Prairie Cordgrass (Spartina pectinata ) — a graceful wetland plant with bending leaves and heavy heads of flowers and seed — is widespread throughout North America. When grown well, it can exceed three feet in height and forms a large clump in a few years. It can be a bit too vigorous in open soil, so you might want to plant it in a pot and submerge it partly or wholly in a water-lily pond. In autumn, when it turns an almost fluorescent yellow, you will have a centerpiece for the garden.
The Silver Dollar Plant (Plectranthus argentatus), an annual, is best used as a filler and a foil to bright annuals in a border. Or you might want to tuck it into perennial borders to cover bare spots where bulbs bloomed. By midsummer, the smallest sprig will form a plush mound of gleaming silver. By summer’s end, it will grow two to three feet tall.
Horticulturists in the Rocky Mountain region know about the Cheyenne Experiment Station and the treasures it contains. The first of these treasures offered through Plant Select® is BLUE VELVET® Honeysuckle (Lonicera korolkowii ‘Floribunda’), which is a large shrub. In a few years, this makes a wonderful mound of silvery leaves that are practically obscured by bright pink flowers in spring and scarlet berries in autumn. Unlike other shrubby honeysuckles, this is resistant to disfiguring aphid damage.
Penstemons are among the best loved Western wildflowers. The first penstemons in the Plant Select® program are a hybrid of the showy Mexican species crossed with much hardier Western natives. They thrive through our coldest winters and bloom from spring to frost with a little dead-heading. RED ROCKS® Penstemon (Penstemon x mexicali) has deep rosy-red flowers with a white eye, and PIKES PEAK PURPLE® Penstemon (Penstemon x mexicali) has deep violet blue flowers. Both have lustrous evergreen foliage.
SPANISH PEAKS® Foxglove (Digitalis thapsi) is perennial and grows from twelve to eighteen inches tall. The clump can form a mat over time. It thrives in shade and considerable sun, provided it doesn’t dry out. This plant was introduced from the mountains of southern Spain.
Lovers of our Western prairie wildflowers know about Winecups (Callirhoe involucrata), which is one of our most adaptable native plants. It thrives in a watered border or a completely dry Xeriscape. The dark green leaves and rosy cup-shaped flowers look like a superior geranium in the landscape.
SILVER BLADE® Evening Primrose (Oenothera macrocarpa subsp. incana) grows alongside Winecups in the southern plains. This plant was selected for its intense silver foliage and tolerance to a range of garden conditions. It blooms from late spring to late fall and is a stunning contribution to dry gardens or the perennial border.
Plant Select® introductions and recommendations are available at garden centers and nurseries. Additional information on the cultural needs of these and other plants in the program is available at the Plant Select® website, www.plantselect.org.