High Plains Gardening
The gardening website of the Texas High Plains Region
AHS Heat Zone 8
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.
Santa Fe phlox is rarely available even at native plant nurseries, but when it is, don't pass it up. Sun loving and drought tolerant, the Santa Fe phlox blooms late spring throughout the summer with once a month watering. Five petaled, small pink flowers about an inch across with a small white eye can cover the plant. Native to canyons, mesas, and rocky desert slopes from West Texas to southeastern Arizona and into northern Mexico. Seeds of the phlox pop out when they are mature, making seed collection and propagation difficult.
Native to the plains, Coreopsis tinctoria, has naturalized throughout most of the U.S., especially in disturbed soil. Prefers moist sandy soil. An annual, it may last more than one year. Very showy flower with yellow outer rays, with a maroon blotch towards the center ray. Sow seeds in early spring. Heat tolerant, once a month watering is recommended for well drained soil.
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).
Golden sulfur buckwheat is one of those plants you'll come across while hiking in the West and wonder why it isn't in your garden, its so adorable!
The leaves are gray-green, spatula shaped and woolly underneath, to about 2-3 inches. They form a rosette at the base. In early spring, tall, stout stems extend upward up to 2-3 feet. The bright golden flowers are nearly luminescent, appearing first as ball-like umbels (clusters), then each ball opening up to a circle of golden flowers. As the flowers age, then turn orange.
A great plant for those people who must have their foliage fix. Despite their large foliage, cannas will do quite well in a medium water-use area with well amended soil.There are dwarf varieties and others that will reach 7 feet. Leaves shred easily by hail, but will recover after several weeks. Cannas sprout from thick rhizomes. Although subtropical, cannas easily winter over in the Texas Panhandle and spread to form a thick root mass.
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.
Gorgeous! Luscious goblet shaped lemon yellow flowers on this native wildflower that also develops elongated seed capsules. The lighter, silvery sheen of the leaves distinguishes the O. macrocarpa var. incana subspecies, and is also an evening to morning bloomer.
There are several varieties of Salvia guaranitica that range in shades of blue from light to dark. As with most of the tube-shaped salvia flowers, S. guaranitica is a hummingbird magnet.
Native to South America, S. guaranitica is not zoned cold hardy for the Texas Panhandle, but it has wintered over in protected Amarillo gardens in many locations for many years. It has wintered over for me at least 5 years, unprotected. Deadheading is not required.
Low growing, drought tolerant evergreen groundcover that becomes covered in tiny sky blue flowers in early spring for about 6 weeks, then sporadically throughout the year. I’ve seen a few twinkling blue blooms in every month of the year. The tiny leaves of V. pectinata are gray-green and tomentose. Allow plenty of room for the spread of this fabulous groundcover; it’ll just keep going and going and going. And you won’t want it to stop.
The Calylophus genus is one of the best Southwest native plants for Panhandle gardens. Heat and drought tolerant, long blooming with little to no care, what garden would be without it? Sunny yellow 4 petaled sundrop flowers bloom in an explosion in spring, and respectably during the remaining growing season, especially when given a once a month inch of water during drought conditions. Each individual flower lasts only a day, tight compact mounds sport the orange spent blooms as well as the new bright yellow flower.
Shadscale lives in alkaline caliche soil in most of its native range throughout the Southwest and has a high tolerance of saline or sodic soils. Given improved soil conditions, it will grow larger. Do not improve the soil to insure it keeps its neat, compact shape. Shadscale blooms yellow flowers in early summer which mature into seed heads. Its silver-gray leaves are semi-evergreen.
Illinois bundleflower should be grown for its unusual characteristics of seedpods and leaves, if nothing else. A member of the legume or bean family, the seed pods turn dark brown, leathery and twisted in appearance and rattle in the wind in late fall. The compound, alternate, pinnate leaves fold when touched or when exposed to strong sunlight. Small white flowers in summer. Attracts butterflies, birds love its seeds. The plant can grow to be quite large if in high water-use areas.
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.
Texas beargrass is a grass-like perennial evergreen plant native in rocky and limestone soils from central Texas to the upper Rio Grande Plains and west to the Trans-Pecos and into S.E. Arizona. Not a true grass, Texas sacahuista is a member of the lily (Liliaceae ) family. It flowers in Amarillo in early April. A short flowering stem barely rises above the many thin leaves. The flowers appear rose or reddish on the outside before opening, are numerous, white to cream colored forming dense vertical clusters.
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.
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.
Exciting perennial ornamental oregano for your low water-use or Mediterranean style garden. Spreads slowly by rhizomes and is easily propagated by root cuttings in fall or early spring. The flowers elongate as the summer progresses, eventually drying to a papery brown by summers end. In a wet fall, some new flowers may still appear. O. libanoticum is best placed to drape over a rock to showcase it’s drooping nature.
1997 Perennial Plant of the Year was chosen for it versatility in growing in many different regions of the US. And it will grow in our Panhandle gardens as well. Although reported to be drought tolerant once established, it does much better in a medium water-use environment with afternoon shade. When it is excessively hot and dry, it suffers from stress, but usually survive. Just give it a little more water when this happens.
Attractive to bees and butterflies. Seedlings may happily appear in springtime. Native to Europe and Central Asia.
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.
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