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.
Delicate fern like foliage for your shaded woodland areas. Will grow in a low water-use zone, however, the foliage will disappear in summer. Delicate tubular, yellow. White and blue varieties have been available locally. An excellent choice for underplanting trees, especially for a medium water-use zone. Will reseed.
Rose of Sharon, or Althea, is another reliable old-fashioned garden plant well suited for the Texas Panhandle. My favorite cultivar is Diana because of the brilliant, pure white 4-5” flowers and somewhat glossy green leaves. Diana is also one of the smaller varieties up to about 6 - 8 feet, while others can reach 10’ tall. Similar to most altheas, 'Diana' is a prolific bloomer.
A long-lived evergreen penstemon for the average bed or border. Small orange red tubular flowers attract hummingbirds, as do most red tubular flowers. Low growing and longer flowering than most, especially the more mature the specimen.
After several years, the pine needle like foliage can resemble a miniature bonsai. Pineleaf penstemon is also a must-have for the low water-use bed or border or rock garden because of its evergreen foliage and longer blooming nature. In late summer, snip off the dried, spent flower heads; some re-blooming may occur.
A Plant Select Plant for 2004, Pink Texas Skullcap has often been listed as a Zone 7 plant, but it is reliably cold hardy in Zone 6 and in protected Zone 5b sights. I’ve grown it in my xeristrip since 2000. Long blooming with no maintenance ever performed. These low growing, mounding skullcaps are excellent for Panhandle xeristrips and rock gardens. Native varieties are S. drummondii, and S. resinosa. The hybrid cultivar, S. x ‘Violet Cloud’, introduced by High Country Gardens, is an excellent violet skullcap as well as the natives.
Not our old fashioned garden zinnia. Zinnia grandiflora is the native zinnia for most of the Midwest, West and Southwestern parts of the United States. So widespread a wildflower, each region has named it theirs: plains zinnia, prairie zinnia, desert zinnia and Rocky Mountain zinnia. A terrific low growing and spreading groundcover for poor soils needing no supplement irrigation. Rugged! A survivor without being a pest!
Desert marigolds are one of the prettiest desert flowers. The plant forms a neat compact rosette of finely cut silvery green leaves from which stems emerge topped with a bright golden daisy like flower. It is considered either an annual or short lived perennial. Scatter seeds from the spent plant to insure its return the next season. Over watering will doom this beautiful plant. Desert marigold can be seen blooming in the desert in winter and spring. In my garden, it's blooms begin in May and will continue sporadically into fall. Not awfully reliable in cold hardiness here.
Agastaches are some of the Southwest's showiest natives and one of our native perennials where must breeding and hybridization is being done. Native to slightly higher elevations that 3600 ft., it requires either afternoon shade or medium water-use. It has not been reliable in coming back for me, but it has for others. Well drained soil is a must. Nonetheless, it is easy to be seduced by its masses of blooms and alluring fragrances. Hummingbirds certainly are entranced.
Cypress vine is a native annual tropical vine of the Americas, but has naturalized in Florida and the Gulf Coast areas; said to be cold hardy to Zone 6. Fine lacy or thread-like leaves twine as it grows, putting on scarlet red flowers in summer. In addition to being a climber, it can be used as a groundcover.
White flowering zinnia is native to the Southwest and Northern Mexico. A low mounding plant, it becomes completely covered with small white flowers with a central yellow disk, similar to our native prairie zinnia, Zinnia grandiflora. Blooms from June through fall. Desert zinnia is toxic if ingested by humans.
New Mexican privet can be viewed either as a tall shrub or smaller tree. New Mexican privet will flower (tiny yellow) before leafing out with small oval glossy green leaves to be followed with black berries in the fall. Heat and drought tolerant will live in most soils and water-use areas. Attractive taller plant for the home landscape, similar to the yaupon holly in form.
Bush morning glory is a non-vining herbaceous perennial with a deep taproot, allowing it to be drought tolerant, but difficult to transplant. Arching branches with narrow upright green leaves emerge from the taproot. Summer blooming with 3 inch pink to purple funnel shaped flowers that open in the morning and close in the afternoon. Bush morning glory typically inhabits sandy and sandy loan plains, meadows, prairies and roadsides.
Herbaceous perennial. Fragrant hummingbird plant belonging to the mint family (Lamiaceae). Limited reseeding. Does better in afternoon shade. Locate in a transition area between medium and low water use. Leave plant and flower stalks standing in the fall, the plant does better trimmed back at the beginning of March.
This pink (old common name referring to the pinked edges) is pink. Heat tolerant fragrant perennial forms a spreading mound. The buds provide interest for several weeks before they open. Other perennial dianthus thrive in our area, biennial and annual dianthus as well. Look for heat tolerant varieties. D. gratianopolitanus ‘Firewitch’ is another dianthus to try. Carnations, maiden pinks, Sweet Williams are members of this genus. There are many hybrid cultivars, and more every year.
Perennial with lyre shaped leaves, similar in appearance to scabiosa, native to central Europe. In fact, it's synonym is Scabiosa rumelica. Deep purple red pincushion-like flowers. Knautia macedonica may suffer from our alkaline soil if not well amended with compost and well drained. Will reseed some. Has a pleasant wild look. Popular with nectar feeding insects. Deadheading doesn’t seem to be necessary.
‘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.
A new hybrid skullcap from High Country Gardens. A cross between two native skullcaps, Violet Cloud likes the soil lean and well drained. A sparkling addition for the rock garden, xeristrip and any low water-use area. Additional watering is required during establishment the first year, after that, it should be drought tolerant.
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.
Sumacs are known for brillian fall foliage. Ground cover woody shrub 24-30" tall with dark shiny green leaves that turn a thrilling orange-red in the fall. Small yellow flowers at springtime.
Big Bend silverleaf is the most cold hardy of the Leucophyllums and has wintered over in Amarillo, Zone 7, for 5 years so far. Possibly cold hardy to Zone 6. It is hard to beat a more attractive summer blooming shrub for small xeric spaces. After summer rainfalls, Big Bend silverleaf, native to the Big Bend National Park area, becomes covered in silver blue flowers that twinkle like jewels among its silvery gray leaves. Hard to find, it's worth searching for.
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.
Attracts butterflies.
Blue grama grass is a short, clumping warm season grass with thin blue green blades that is native throughout the Great Plains and Southwest. Able to grow in poor, dry soils, blue grama grass needs only about 12 inches of annual precipitation to survive. If seeded thick enough and with moderate irrigation, blue grama will form turf. Once establish, reduce to monthly supplemental irrigation, and mow not more frequently than monthly to a height of 4 inches. One advantage of blue grama over buffalograss is the speed of germination; it will germinate in 5-7 days.
Yaupon holly is a tall shrub or a small tree growing typically to 8-12 feet in the Texas Panhandle. Cold hardy to Zone 7 (still best to plant in a protected location), it prefers partial shade, especially afternoon shade. Low (once established) to high water use. Small leathery, glossy, evergreen, dark green leaves (to 1.5” long) have toothed margins on dense branching. Insignificant greenish white flowers in springtime followed by red berries in the fall. Female plants require a male plant to pollinate and bear fruit (dioecious). Attractive tall, traditional looking shrub.
Gayfeather is one of the High Plains jewels of autumn, sending up grasslike leaves or stalks that bloom gloriously in September and October to fuzzy purple spikes. At maturity, one plant can grow a dozen or more, size and number depending on rainfall amounts. Drier years, the stalks are few and short, but with monthly or twice a month watering, the plant displays much more vitality. The purple flowers contrast nicely with the many yellow flowers that bloom on the plains. Liatris punctata is the most drought tolerant of the genus.
Old fashion garden and English cottage garden herbaceous perennial that works well in the Southwest Cottage Garden. Hollyhocks are considered to be either a biennial or perennial. They produce copious seed but are not considered invasive or troublesome. Plant seed in the fall, or early spring. Avoid watering the foliage if irrigating, a drip system works better that above ground sprinklers.
Perennial from South Africa noted to be cold hardy for our area, but I’ve had mixed results, most years it didn’t winter over (although reported to be Zone 5). However, it will flower nicely the first year in the garden, so I’ve kept trying it. A Plant Select Plant for 2000. Perhaps it needs moister conditions in the winter than what I give it.
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