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.
The only draw back to this pretty, silver-edged groundcover is its flowers! If only it didn’t, it would be a perfect no maintenance, no water groundcover for hot, sunny locations. You can see the tiny ball shaped flower heads in the picture, which look rather indistinct. However, after flowering, they turn an ugly shade of brown that mar the beautiful leaves unless you shear them off. Though a creeping groundcover, silver-edged horehound is not invasive like the common horehound, M. vulgare.
‘Mersea Yellow’ is similar to the orange red pineleaf penstemon in culture, except for requiring a bit more water. Native perennial to the Southwest. Its leaves are lighter green, but still evergreen, without the tinge of mahogany in winter. ‘Mersea Yellow’ is an excellent selection for the medium water-use zones of your landscape. One of the few yellow flowering penstemons.
There are numerous interesting yuccas to choose from besides the Yucca glauca or Y. angustifolia seen throughout our area. Y. filamentosa ‘Color Guard’ has some of the most striking variegation and will even flower in part shade, cold hardy to Zone 5. Other Y. filamentosa varieties to consider growing in our area are ‘Bright Edge’ and ‘Golden Sword’.
If I had to pick my favorite plant, this is it. Long blooming and drought tolerant with only minimal maintenance of late winter cutting back, and maybe a bloom pick-me-up deadheading at mid summer. It will also re seed some so you’ll have more of them the next year. It’s fragrance is light and pleasantly of sage. Salvia greggiis are native to Texas in the Kerrville area. It is my favorite, but not the absolutely perfect plant. The stems are quite brittle and very easily break or snap off, even when you’re carefully weeding around it.
Previously known as Cowenia mexicana, it is known today as Purshia stansburyana, also, P. stansburyiana. It is still commonly called a cliffrose. The cliffrose blooms prolifically in May with creamy white to pale yellow fragrant flowers that continue blooming for several weeks. Semi evergreen, it loses it's leaves in colder winters. Upright stems and branches can appear unruly in its growth pattern; small dark green resinous leaves.
Texas betony is a workhorse of the garden once established, putting on a plethora of scarlet blooms midsummer on. A member of the mint family with square stems, the foliage is fragrant, but the plant is not invasive as classic mints tend to be. Hummingbirds love Texas betony. Though native to the Southwest, it is found in moist crevices and steep, stony places in the mountains in moist, well-drained sand, loam, and clay. Texas betony is said to be cold hardy to -20°, however, I have not found it reliable in returning each winter. Yet, it is worth replanting.
Lantana urticoides (horrida) is a native perennial, and cold hardy for most of the state, except for areas in the Texas Panhandle. In the Panhandle, several species of Lantana are sold as summer bedding plants. Blooms prolifically summer and fall. Colors normally available are red, red and yellow, yellow, white and purple or mauve. In rare cases they may winter over. In areas south, lantana will grow into a shrub. The blue/black fruit clusters are poisonous.
Buffalograss is North America's only native turfgrass, grows well in clay soils. A warm season grass that spreads by stolons, it is our best selection for low water-use lawns. It will survive very nicely on 15-20 inches of annual precipitation. For green turf summer long, a once a month watering is all that is needed. The common species is short to 4-8 inches, light gray/green to blue/green and goes dormant in fall, greening up again in May. Many newer varieties are being developed for wider blades and deeper green colors, such as Legacy® and Turffalo®.
Junipers are native to much of the U.S. and come in many sizes and shapes. Juniperus horizontalis is the low growing and spreading juniper, used mainly as an evergreen groundcover. There are many varieties available, one or more to suit every purpose and location. Colors and heights vary from the common dark green evergreen to blue green, blue and even lime or chartruese. Their hallmark is their fine texture, many of the newer varieties have a pleasant soft touch. Water use can vary as well, but typically, once established many will thrive on once a month deep watering.
Showy evening primrose is a plains states native, including the Texas Panhandle. Showy evening primrose blooms whitish pink in late spring, with each flower lasting a single day, opening in the morning and closing later in the day. The leaves are green narrow and lance-like and emerge from spreading rhizomes. The plant spreads prolifically by rhizomes and seeds, especially in amended and well watered soil. It is not well mannered in a mixed bed or border, I consider it invasive for the garden.
Karl Foerster feather reed grass is a cool season bunch grass one of the best ornamental grasses for a medium or high water-use area. In a low water-use area, it will take longer to reach mature height and width (the more water it gets, the bigger it'll get). Karl Foerster feather reed grass suffers in the xeric bed during the hotter, drier drought years and may die out.
A beautiful white variety of the purple coneflower. This picture doesn't do the flower justice.
Similar to the purple coneflower, this white variety is really a high water-use plant that appreciates afternoon shade. Deadhead to prolong the bloom period, but keep end of season blooms on for fall and winter interest.
Heucheras are native to the North American continent and make wonderful foliage and flower plants for your woodland border. Grown mostly for its interesting, evergreen foliage, coral bells will continue to flower on mature plants if kept deadheaded into the summer. Although the native heucheras are great in themselves, there are hundreds of hybrid cultivars to choose from.
Russian sage is a must have shrub for every low water-use landscape. Russian sage is used extensively throughout our southwest landscapes, planted along with Buddleia, Carl Forester Reed Grass, Salvia greggii cultivars, Anisacanthus quadrifidis wrightii and Hesperaloe parviflora. It is hard to beat its use where a long flowering, showy, low care, drought tolerant shrub is needed.
Yuccas for Texas High Plains Landscapes
Native woody shrub to Texas, New Mexico and west to California from 3000 to 8000 feet in elevation. It is best to plant in soil with only inorganic amendments. It becomes more floppy and flowers less when fed and watered well. This is a case of less yielding more.
Reseeds some. I've never seen this as a problem. Locate in a sunny area with full exposure to the sun for best growth and backlighting. If planted against a wall or fence it will lean towards the sun and looked tipped over.
Scarlet globemallow is a welcome addition to any xeric or High Desert garden. Small coral flowers bloom from May (sometimes April) through into the fall. Although scarlet globemallow will survive with no additional moisture in our climate, once a month watering insures steady blooms. The plant is similar in appearance to S. ambigua, which can bloom coral, white, lavender and pink.
The Arizona rosewood is classified either as a quite tall shrub or short to mid height tree. One of it's best features is that it is evergreen, with slender glossy green leaves approximately 3 inches long. It puts on small white flowers in summer. One of the few drought tolerant, native, evergreen trees available in the trade. Slow growing.
Yellow honeysuckle is a much better choice, along with Loncera sempervivens, than the traditional and invasive Japanese honeysuckle usually sold. Fragrant and yellow blooming, a good climber and groundcover. Average garden soils with low and medium water-use. Can be low water-use once established.
Sand lovegrass is a warm season bunch grass typically found in sandy soils east of the Rockies over a wide range of the U.S. The grass clumps themselves are usually 12-18" tall with the plumes rising to 3-4 feet. Will grow in clay and poorer soils. Very pleasing wispy, arching habit with a soft sway and rustle in the wind. Can grow in partial shade. Seed heads are somewhat purple, fine textured. Will reseed. Low or no water-use.
One-seed juniper is the juniper found in the dry hills and mesas throughout our area and the Southwest in elevations from 3500 to 8000'. Slow growing on top, it's tap root grows quickly and deeply, making them very difficult to transplant. It's habit is shrubby with several stems and branches growing low to the ground, making it a good habitat plant. Extremely drought, heat and cold tolerant.
Prairie verbena is one of my favorite plants, it is one of the first to bloom in the spring and one of the last to be affected by freezes in the fall. Small in stature, but it has my respect for giving so much with so little given (from me) in return. It's short lived, maybe just one year or three. Green, finely cut hairy leaves, with several branched stems that put on clusters of tiny lavender, purple, violet or pink flowers. Blooms from spring to fall. Readily reseeds, not invasively so. Its volunteer seedlings are easy to dig up and transplant.
Native to the Texas Panhandle, the south and into northern Mexico. Strong chocolate scent fills the morning air. Xeric herbaceous perennial with a deep taproot. Flower closes up during the heat of the day, staying open during more moderate days. Good choice for naturalizing. Best to keep soil on the lean side, will grow leggy in amended soil. Reseeding profusely. Cut back flower to base at end of June if it becomes too leggy. Within weeks, it'll grow back and begin flowering again.
First class native wildflower for your low water-use location whether you live in the city or country. No soil amending is even needed for Engelman's daisy, but you might want to improve the drainage if you soil is compact, or amend with some organic matter for caliche soil. Toowell amended soil will cause E. pinnatifida to grow too tall and gangly. If this happens, cut down nearly to the ground at the end of June, or mid July. It will grow back and begin flowering within 3 - 4 weeks. Will reseed some.
Echinacea angustifolia is the herbal echinacea. Native throughout most of the Midwest, and the Texas Panhandle. Very drought tolerant. It can be seen growing along roadsides and in nature generally. A good cut flower. The common name Black Samson refers to its roots. Not as showy as E. purpurea and newer introductions.