A perennial plant is a plant that requires one or more years to reproduce and usually continues living, but not indefinitely. Whether a plant is cold hardy or not is not connected to being an annual, perennial or biennial.
If you find yourself in Palo Duro Canyon at the end of April or beginning of May, the purple haze dotting the cliffsides is feather dalea. Sporadic blooms will open after showers throughout summer, though never as profuse as in springtime. With monthly irrigation in a xeric garden, feather dalea adds color and texture with it's twiggy, but sturdy, appearance. Small purple flowers combined with white plumes carries the haze impression from a distance.
Warm season native clumping ornamental grass that is well suited to the transition zone between turf and flower bed. Medium to blueish green thin grass blades form a low to medium size clump, medium water-use zone. In late September, it sends plumes upward that give the appearance of a deep pink haze or mist. There are several new selections of Gulf Coast muhly, thankfully, to choose from. Be sure to pay attention to the cold hardiness for your area and you won't be disappointed.
Similar in form to Callirhoe involucrata, Callirhoe alcaeoides 'Logan Calhoun' grows natively from the Midwest to southern plains. While Callirhoe alcaeoides can be pink, to pale pink and pale lilac, 'Logan Calhoun' is pure white. Spreads over an area similar to wine cups, the foliage and flowers are finer. I've found it to be drought tolerant; water monthly to insure continued blooms. Blooms will rest during the heat of the summer and continue following rains or cooler weather.
Raspberry hybrid bush sage is very similar in appearance to Salvia greggii, blooming April through November. It's two-lipped flowers with a pleasant deep raspberry color, and the mahogany calyces contrast nicely. 'Raspberry Delight' is a hybrid cross between Salvia greggii 'Furman's Red' and and a high altitude collection of Salvia microphylla from central Arizona. Woody and brittle branches with small oval shaped leaves that hang on to the plant sometimes through the winter, as they do on S. greggii.
Curl leaf mountain mahogany is a medium height evergreen shrub native to elevations between 5000-10,000 feet throughout the Southwest. Small oval shaped dark green leaves lightly curl under at the margins are evergreen and aromatic. Small yellow flowers in spring time that develop into grain size fruits with a feathery tail attached to one end (similar to other mountain mahoganies). Slow growing and long lived, it can reach a height of 20 feet or more, but is more typically 6-12 feet. Densely branched. Cold hardy, drought and heat tolerant.
Western sand cherry is a shrub native to the northern plains favoring sandy soils. Cold and heat tolerant, and low water-use once established. Beautiful, fragrant white flowers in spring time, producing edible black cherries (however, some references advice not to eat the fruit if it is bitter).
Many Aquilegia’s are native to the U.S. Golden columbine, Aquilegia chrysantha is a Texas and southwest native, has yellow flowers and can take more sun than some varieties. McKana's Giant is the hybrid columbine most often sold. Large beautiful bi-colored flowers dazzle in woodland and shady area. Rocky Mountain columbine, Aquelegia caerulea; and wild columbine, A. canadensis, are other common columbines. Rocky Mountain columbine is the state flower of Colorado.
Centranthus ruber is a versatile plant, able to be used almost anywhere in the landscape except full shade. Long blooming except during the heat of the summer. Deadhead after the spring bloom for better appearances. Reseeds some, but not a problem. Quite drought tolerant, it will still do nicely in medium and high water use areas, except for wet, soggy clay. It appreciates good drainage and moderate amending but will do well in poor soil. Centranthus ruber 'Alba' is a pleasant white blooming variety. Readily available at local nurseries.
Cranesbill belongs to the same Geraniaceae family as do the Pelargoniums, those red, hot house geraniums we all love. Both are perennials, however many cranesbill (referred to as the true geraniums) are cold hardy for us. Alpenglow is semi-evergreen, and evergreen in warm winters. Notice the intricate cut leaf patterns, which are much admired by myself and others. A good understory plant for the edge of a shady border.
This is not one of the invasive catmints, but it will reseed some and is not as attractive to cats as most catmints. A low growing, sprawling, drought tolerant perennial that projects a hazy blue appearance with its light lavender blue flowers and grayish green foliage. It is aromatic, not necessarily fragrant. A fast spreader and prolific bloomer even in it's first year, it will begin to bloom after six weeks.
Rudbeckia is advertised as heat and drought tolerant, but I have not found it so. I’ve found it to require at least weekly watering during the heat of the summer. A shortlived, southern native perennial, it likes the humidity and rain from southern climes. These very large and stunning composites may be worth your effort, just place within the correct hydrozone.
Exciting drought tolerant groundcover! This gray-green leaved, evergreen groundcover adds quite a sparkle to any xeristrip or low water-use bed, border and rock garden. For prolonged summer blooms, water monthly during the growing season. Needs full exposure to sun and little water. Like's it's soil lean.
Delightfully fragrant with a sweet honeysuckle scent. A truly beautiful addition to any xeric bed or border.
Dark green, semi-evergreen aromatic leaves are the feature most prized, along with the tiny yellow daisy-like flowers that bloom spring to fall. Damianita prefers full sun and lean soil and does well in heat and temperatures to zero degrees. Daminaita will lose its leaves in cold winters.
Golden current makes an attractive taller shrub at the edge of a lawn or vegetable garden, positioned to catch extra irrigation water. For three stunning weeks in spring it will be covered with tiny yellow flowers. I planted two in 2008, and have yet to notice the tasty berries, red currents, for which they are known. Quite cold hardy, if placed in full sun, it'll need twice a month watering to survive, or in half or more shade, once a month watering is sufficient. Multi stem shrub with small, rounded leaves with cut edges makes an attractive barrier or hedge plant.
People either love trumpet creeper or hate it. The first three years, I couldn't wait for it to mature, filling with red-orange trumpet shaped flowers. It seems I've spent the next 20 years trying to kill it. Trumpet vine will die, but only for those who want it to live. If a gardener gives it the death wish, it will be sure to flourish. Native to most of the eastern half of the U.S., it is low water-use, thrives in heat. Must be in a sunny location to bloom profusely. Considered to be invasive, especially when over watered. Not particular about its soil.
Gooseberryleaf globemallow is very close in appearance to scarlet globemallow, Sphaeralcea coccinea, but much taller, up over 2 feet. The leaves are silver green and hairy, resembling the leaves of the current shrubs in shape, so named from the family name of currents and gooseberries, Grossulariaceae. Flowers are orange in color and bloom from May and June, sometimes later in the summer. Native to hot, dry areas semi-arid regions throughout the Southwest and the Great Basin Desert. Prefers good to sharp drainage.
Mountain mahogany is native to the Texas Panhandle and throughout the Southwest, found in elevations from 3000-9500 ft. Another common name is Alderleaf mountain mahogany, because its leaves resemble that of an alder. Mountain mahogany, whose wood is very hard (Palo Duro) is found in Palo Duro Canyon. Extremely drought tolerant, it will survive on 10 inches of rainfall. An aromatic shrub with shredding reddish bark, but can grow to tree size. Mountain mahogany's flowers are small, rayless and insignificant, as they are in the other species.
Gambrel oak is a common native oak species throughout the Rocky Mountain foothills and here in the Texas Panhandle as well. Often times it grows more to a tall shrub, with sufficient moisture it can mature into a small tree. Beautiful somewhat glossy lobed green leaves to 3-5 inches long. Beautiful fall foliage. Will put out a profuse amount of acorns. Gambrel oak can form a thicket. Cold, heat and drought tolerant. Inconspicous tiny red flowers appear shortly after leafing and are normally hid by the leaves.
Delicate and fragile in appearance, columbines are some of the most durable, versatile plants in the West. Aquilegia chrysantha is the Texas native columbine, happy in both sun or shade, moist areas or dry. Aquilegia chrysantha is native to the Chihuahuan and Sonoran Desert canyons from west Texas, southern New Mexico, southern Utah, and Arizona south into Sonora, Coahuila, and Nuevo Leon along with a disconnected population in southern Colorado.
An old world Mediterranean plant best known for the acanthus leaf shape used as a basis in classical Greek and Roman designs. The plant itself takes 2 – 3 years growth before flowering. Attractive flowers with purple bracts on tall spikes to 4’. Frost sensitive, will die back in a late spring frost, but will come back. Adds architectural and textural interest.
A good drought tolerant ground cover for use in a border, in a xeristrip or a rock garden. Evergreen grayish green leaves with fine hairs (tomentose). Will grow too tall and gangling in too rich and moist a soil. Some areas of the country have noted Cerastium tomentosum to be invasive, but I have not seen those tendencies here. A good substitute for the annual alyssium. Cerastium tomentosum var. columnae is a commonly available variety.
I love ornamental grasses and this grass tops my list. Blueish green evergreen leaves. A cool season clump forming, medium height grass. Treat it as medium water-use for the first year or two. Blue avena grass is not particular about soil, just as long as it’s well drained. After 2-3 years, blue avena grass will put out light tan oat-like plumes. This grass performs better in afternoon shade.
Drought tolerant perennial with white cup shaped blooms usually found growing in poor soils. I planted it in heavily amended soil, and I think it was too rich for it. It was eaten up during the heat of the summer by flea beetles. I thought the too rich soil was the cause; however, Judith Phillips in Plants For Natural Gardens, wrote about this same occurrence in native soils. Phillips hypothesized this may be a way for tufted evening primrose to escape summer’s heat. However, my plant died, rather than just going to ground.
The flowers of Salvia darcyi are similar in appearance to Salvia greggii, however the shrub itself is more herbaceous than shrubby. I know of no common name for S. dacryi. Some sources say it is cold hardy to Zone 7, however it thrives in Denver Botanical Garden’s Zone 5. S. darcyi is native to the mountains of Northern Mexico and will do well in amended soil. Hummingbirds love it.
I have it planted in my xeristrip for a number of years. It will flower more vigorously with irrigation everyother week, when needed during hot drought years.