Plants that will live in areas that experience 90-120 heat days (AHS Heat Zone 8) each year where temperatures exceed 86 degrees F. Except for a few limited areas in the Texas Panhandle, our AHS Heat Zone is 8. Plants rated lower than AHS Heat Zone 8 may not survive the summer's heat.
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’.
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.
Snow on the Mountain is a showy plant native to the plains states. Heat and drought tolerant in the Texas Panhandle. Striking variegated green and white foliage, with small white summer flowers. Can be invasive and is toxic to humans, sap of plant may cause dermatitis. Deer resistant. Control spread by deadheading.
Elegant and stately desert perennial. Soft light blue green leaves. Stalks can tower above desert shrubs to 5-6 feet, but usually 2-4 feet, with racemes of yellow flowers similar to cleome or spider plant flowers in springtime. Requires excellent drainage and lean soils. Thrives on selenium rich soils. Native to canyonlands in SW U.S.
Ephedra minimus is a dwarf version of E. viridis. Woody base with many thin, branched evergreen stems. Rare to find in nurseries, it is appreciated for is evergreen presence and rarity. No leaves or flowers
Shrub live oak, often a medium size shrub, is native to the Southwest and the Texas Panhandle typically found in canyons, rocky cliffs and hillsides. Sometimes called a holly oak, the leaves are 3-4 inches long, spine-tipped and holly shaped bluish green leaves. It is prolific in putting out acorns. Cold hardy, heat and drought tolerant.
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.
Although usually sold as Clemantis paniculata, it could be C. terniflora. Sweetly fragrant, low water-use vigorous growing vine for great late summer display. Creamy white flowers form silvery seed heads. Cut back in spring as it blooms on new growth.
Green sword-like foliage with striking bell or funnel shaped flowers that last only a day. Hundreds of different hybrids and cultivars in a wide range of colors, some early, mid and late summer blooming. Daylilies do better in medium, well-amended soil and a sunny location that enjoys afternoon shade, but they are versatile. Daylily leaves may exhibit alkalinity in clay soil. If this is the case, amend well with organic matter.
Although there is question in my mind whether pavonia is a native in Texas, it’s been naturalized for a long time and is found growing in the Edwards Plateau and south Texas. Pavonia has been cold hardy for me for at least 5 – 6 years. Readily reseeds to the point of being a nuisance, but this is a minor annoyance.
Unlike, S. nemorosa ‘May Night’, I don’t mind deadheading this salvia, perhaps because of its plum color it does not require as persistent deadheading. Notice the gray-green leaves of ‘Plumosa’, versus the green leaves of ‘May Night’. The stems tend to flop, but the flower stalks continue to grow and flower upright -- very strange.
Yuccas for Texas High Plains Landscapes
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.
Broom snakeweed is a small mounded subshrub with yellow greenish thread-like leaves, native throughout the Southwest and western half of the North American continent. In the fall, it becomes covered in small golden yellow flowers. Bees and nectar butterflies are attracted to it in numbers. Usually grows to only a foot tall.
Western ironweed is a prairie native to the Great Plains states. Mid-summer to fall deep purple flowers clusters appear at the top of stalks. Ironweed can be invasive, rooting madly down to a foot so control could be difficult. Drought tolerant and cold hardy for the right location.
Turpentine shrub is an evergreen shrub native to the southern parts of the Southwest, and only marginally cold hardy on the Caprock. It will survive when in a sheltered location and soil with excellent drainage, along rocky cliffs, outcrops and arroyos. Avoid compact clay soil, or amend clay soil very well for drainage with inorganic amendments. Yellow autumn flowers.
Three leaf sumac is medium height woody shrub native to the Texas Panhandle and throughout the Southwest. Three distinctive cleft and lobed leaves (trifoliate) are medium to dark green. Small greenish yellow flowers in spring are followed by tart red berries in summer, which are used to make a lemonade-like drink. The shrub's flowers have a pleasant fragrance, even though it is called skunkbush by some. Beautiful golden and reddish fall foliage. Cold hardy to Zone 4, yet extremely heat and drought tolerant. Prefers sandy and well drained soils.
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.
The old fashioned larkspur is a drought tolerant reseeding annual, previously associated with delphiniums (now in the Ranunculaceae family). I’ve grown it in my alley, in the xeristrip, and its crept into my medium water-use zone. Deadheading keeps millions of tiny seeds from overcoming your garden next year, and also keeps the blooms coming. Larkspur can flower for six weeks. Again, deadheading is important to prevent a massive infestation throughout your landscape.
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.
‘Red Rocks’ is another hybrid cultivar, named for the Denver, Colorado red sandstone area and amphitheater. P. 'Red Rocks' is highly suitable for the average garden, rather than a specialized penstemon bed. Again, do not deadhead unless reblooming has occurred and you desire a tidier appearance. Don’t over water or over amend the soil, but it will thrive companionably with other medium water-use plants.
Scabiosa columbaria ‘Butterfly Blue’, though first discovered in Ireland, will thrive very nicely in your transition zone as a border plant along turf, where it’ll receive medium to medium high water. Amend the soil well with organic matter for rich blooms and keep it deadheaded to prolong blooms. Afternoon shade is recommended. A little more trouble than usual, but well worth the softening effect this compact, mounded and cheery plant brings to the border; a Perennial Plant of the Year for 2000.
Grown extensively throughout the southwest, I don’t know why it has taken so long for this plant to become available in the Panhandle, especially since it is cold hardy to Zone 5.
It is a bit slow to become established, and late in coming out in the springtime – have patience and place a marker so it’s not forgotten and weeded up. Note: Early spring-emerging plant may look similar to bindweed. It is best to plant this wild fuchsia in spring, rather than the fall. I noticed better success with quart to gallon size plants.