Plants that can survive and even thrive with little water are always valuable in Colorado where we get 15”-18” of precipitation most years. But when a real drought comes or when limited snowfall in the mountains means water restrictions down here, then xeriscape plants are essential in our gardens
Because the well at Harlequin’s Gardens nursery is so poor, my rockery garden has been on water restrictions for the last 25 years. Here are some plants that have performed well in my garden that is watered only 3 to 7 times a year.
Genista lydia is an evergreen subshrub, only 10”-12” high and 2’-3’ wide, with thin arching stems. The pea-like flowers are bright yellow and completely cover the branches when in bloom in early summer. It looks good as a single specimen, spilling over a mound or rock. The compact size and long flowering period allows attractive partnering with white, orange and blue-flowering perennials. Genista lydia looks like a miniature broom (Cytisus), but has been more drought resistant in my garden.
Glaucium acutidentatum is a Horned Poppy. It is called “horned” because the long, thin seed pods are arching and slightly pointed. And the 4-petalled flowers look very much like a poppy, especially this orange variety with its black basal spots. The foliage is very bold and architectural, of a silver-blue color and is evergreen. In spring the rosettes extend upward into flowering stems, and the plant expands to 2’-3’ in diameter and 18” high. The orange flowers are very showy for a long time. They do self-sow prolifically, so it is best to dead-head at least part of the seed pods before they split and drop seeds. It is good to prune down the flowering stems before winter to let the new foliage fill in. Glaucium acutidentatum has significant drought tolerance with its deep tap root.
Keller’s Yarrow, Achillea kellereri, is not your run-of-the-yard yarrow. This gem grows 12’-16” in diameter and 10”-14” high and has neither run nor seeded for me. The gray-blue foliage is delicately cut and the flowers are bright white with a yellow eye, appearing in small clusters on the stems. It has a long flowering period and naturally attracts butterflies and other pollinators. Keller’s Yarrow has been long-lived in my xeriscape garden. It helps to cut off spent flowers and give a deep
watering after the bloom period.
Anthemis marschalliana has exquisite filigreed, very silver foliage. It is a perennial from Western Asia, growing 4”-10” high and 12”-20” wide. The low mat of foliage really sets off the rich yellow daisy flowers on thin stems. It can bloom for weeks, especially if watered once a week during flowering. It bloomed bravely in my garden for several years before disappearing last year, perhaps down the hatch of the grasshopper mob. Filigree Daisy was well chosen to be a Plant Select winner for 2012.
Mount Atlas Daisy, Anacyclus pyrethrum depressus, has a deep tap root and loves self-seeding in rocks. Its feathery foliage looks delicate, but is tough enough for some foot traffic. The daisy-like flowers are white with a yellow center, and when the flowers fold up at night, the backs of the petals are a showy red. The rosette radiates outward as it goes to flower, then drops its seeds and draws back into the crown. Atlas Daisy is not choice enough for a rock garden, nor solid enough for a ground cover, but it is a tough, drought tolerant and showy friend in a rockery, along a path or at the foot of a shrub.
Gas Plant or Fraxinella is botanically Dictamnus albus ‘Purpureus’ and D. albus. My wife, Eve, got me interested in this plant several years ago. It was growing beautifully in her garden, and she thought it might live in my xeriscape. It took three years to get big and bloom, but now it is very successful, and like a peony, could outlive me. Here is part of her description: “Fraxinella develops into a beautiful dense plant with the presence of a compact shrub, 2’ to 3’ tall and wide. It is weather-resistant, sturdy, and upright with handsome pinnately compound foliage and bold upright spikes clothed in lovely 1” to 1 ½” florets that are pink with dark veins. Dictamnus is hardy to zone 4 and thrives in full sun and part shade. In hot weather, it emits a small amount of gas that can be lighted for a momentary flash. It is quite drought tolerant once well established.”
I wouldn’t water any of these plants more than once a week, except maybe in July. It isn’t necessary to be in a water crisis to find them attractive. But if we do find ourselves under water restrictions, these plants will perform admirably. It could serve us well to train our gardens to grow on the dry side.