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.
Typically a Zone 8 plant, the Christmas holiday bulb, Amaryllis, has been successfully wintered over in Amarillo, specifically, the Wolflin area in this case. If you have a warmer, protected micro-niche, try planting your seasonal Amaryllis outdoors, and leave it there well mulched over winter. I 've winter over Amaryllis in my backyard, but it hasn't reliably bloomed. It requires a full sun location and well amended soil to soak up nutrients to be stored in the bulb.
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.
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’.
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.
Two southern native hibiscus suitable for the medium to high water-use garden. Large green leaves are superseeded by very large and showy flowers. H. moscheutos is cold hardy and has some of the largest flowers, up to a foot across in red, rose and white, usually with a red eye. H. coccineus blooms scarlet 3 inch flowers -- not cold hardy but worth trying as a specimen container plant.
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.
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.
Artemisia versicolor 'Sea Foam' is mostly grown for its gray foliage. To keep it's desired compact shape, cut off flower stalks after blooming, which is its only maintenance. Soft, rubber-like feel to its short, clustered, needle-like appearance on short 1 inch wide columns. It gives the impression of a coral bed in your rock garden. Not invasive. 2004 Plant Select Plant.
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.
A tuber mostly grown in containers or a summer groundcover, not considered cold-hardy in the Panhandle. Striking purple-black foliage with small light magenta flowers, similar in appearance to bindweed. Ipomoea’s are members of the bindweed family, Convolvulaceae. One bad relation doesn’t have to trash the family, however.
‘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.
Yuccas for Texas High Plains Landscapes
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.
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.
Native herbaceous perennial to the central and eastern U.S.; will grow in a variety of soils, including poor soils. False blue indigo did not flower the first year. Flowering improves as the plant matures. The foliage may go dormant and disappear towards the end of summer. Baptisias belong to the pea family (Fabaceae), a legume. Flowers are similar to a lupine. Other species colors are white (B. alba) yellow (B. sphaerocarpa), and other variations and cultivars, including 'Chocolate Chip', which features a light reddish brown flower, similar to milk chocolate.
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.
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.