What group of plants has the longest proven record of success in Colorado for enduring the radical ups and downs of our weather, including droughts? Our native plants, of course. And if we give them similar conditions to what they have in nature, they will succeed with little care. Here are a few of my favorite native plants that have thrived in my xeriscape garden for the past 10-15 years.
Liatris punctata, the Dotted Gayfeather stores its energy in a thick taproot that helps it produce flowers even after a dry summer. The tufts of rough, narrow leaves are little-noticed until they shoot up their thin flower spikes to 10”-16”, and burst into bloom with lavender-violet “feathers” in August or September. They are especially dramatic in groups of four to ten plants, and they can continue to bloom for a month or more. Liatris punctata is native to the foothills and plains of Boulder County, and unlike cultivated varieties, needs no supplemental water once established.
One of the most abundant and showiest penstemons in the Boulder area is Penstemon secundiflorus. The long spoon-shaped leaves are blue-gray and are very architectural, cupping against the 10”-16” stems. The spring-blooming flowers are a bright lavender-violet and look best in a drift. After they bloom, I dead-head half the flowers to keep the plants longer lived, and then when the rest of the seeds are dry and ripe, I crush the seed pods in a gloved hand and scatter the seeds to add to my drift. Like most penstemons, this one is drought tolerant.
Calylophus serrulatus is sometimes called Oenothera serrulatus, but this “evening primrose” like perennial is more of a subshrub and it blooms all day long. It is densely branched to 6”-8” high and 8”+ wide, with glossy toothed leaves. Its glory is the covering of beautiful yellow 1” four-petalled flowers which can bloom from May to August. It is well behaved and long lived, needing little or no water once established.
There are many great native shrubs for the xeriscape garden, but one of the most attractive is Cliffrose, Cowania mexicana. In late spring this 3’-8’ shrub is clothed in creamy yellow, five petalled, rose-like flowers that have a sweet fragrance. The leaves are small, toothed and nearly evergreen, and the bark gets shaggy with age. Although it looks somewhat delicate, Cliffrose has done well in my unwatered area, staying only 3’ tall, but blooming nicely every year.
In a dry year, flowers are few in the fall, but there are several natives we can count on for bloom. One is Rabbitbrush and whereas not everybody has a garden that can accommodate the big, lanky variety, there is a dwarf variety that can fit into the most sophisticated urban setting. Chrysothamnus nauseosus var. nauseosus is not as sickening as the name implies. It forms a neat mound of fine-textured blue or green foliage 12”-24” high and wide. The flowers, like those of the taller form, are in masses of golden yellow. If the flowers are sheared after blooming, the form remains tidy and it will not self-sow. This plant is extremely drought tolerant and could be used as a short hedge or a specimen, far from the reach of the hose.