USDA Hardiness Zone 6

Plants are known to be cold hardy to at least -10°F.

Other Cold Hardiness categories

Common Name: Gro-Low Sumac

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.

Common Name: Sunflowers

One of North America's favorite annuals. There is much variety in size and colors of flowers, ranging from yellow, golden, orange, red/orange, red and mahogany. The plants themselves can vary from 3-4 feet to 8 feet or more. Seeds sown in springtime will be insure blooms in late summer or fall. Great for cut flowers.

Common Name: Maypop, Passion Vine

Maypop, or passion vine, is a perennial vine native to eastern and southern areas of the U.S. In the South, maypop grows into a woody vine, but in northern areas like the Texas Panhandle, it will die back to the ground. Lobed, dark green leaves, beautiful, unique flowers emerge in the summer to fall, producing edible fruit. Maypop will sucker, especially when ample watering is present. Passion vine, the most cold hardy of the genus, should be cold hardy to Zone 6.

Common Name: Narrowleaf Mountain Mahogany, Littleleaf Mountain Mahogany

Littleleaf mountain mahogany is the shortest of the mountain mahoganies usually sold. Small, narrow, leathery looking evergreen leaves on many intricate branches. Small yellow flowers in springtime and feathery seed plumes in the fall. The shrub is densely branched and slow growing.

Common Name: Gambel Oak

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.

Common Name: Columbine, Golden or Yellow Columbine

Delicate and fragile in appearance, columbines are some of the most durable, versatile plants in the West. Aquilegia chrysantha is the Texas native columbine, happy in both sun or shade, moist areas or dry. Aquilegia chrysantha is native to the Chihuahuan and Sonoran Desert canyons from west Texas, southern New Mexico, southern Utah, and Arizona south into Sonora, Coahuila, and Nuevo Leon along with a disconnected population in southern Colorado.

Common Name: New Mexican Agastache

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.

Common Name: Coral Canyon Twinspur

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.

Common Name: Red pincushion flower

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.

Common Name: Pineleaf Penstemon

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.

Common Name: Butterfly Blue Pincushion Flower

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.

Common Name: Hardy Hummingbird Trumpet, Wild arizona fuchsia

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.

Common Name: Blue Mist Spirea

Rarely does a shrub feature as much versatility as the blue mist spirea. It will grow and flower in sun or shade, low water-use or high. This Caryopteris, a hybrid itself, normally blooms in a pleasant light blue, but other selections have deeper blues hues. Summer blooming into fall. And as unlikely at it seems for hybrid to set viable seed, blue mist spirea reproduces itself pleasantly, never invasively. Indeed, any little volunteers are welcome.

Common Name: Artemisia x 'Powis Castle'

Low water-use non-native hybrid shrub (Artemisia arborescens x Artemisia absinthium) from Europe and Asia. Vigorous grower, do not overwater. Coldy hardy to Zone 6. Ever-silver with elegant finely cut leaves. 'Powis Castle' is named for Powis Castle in Wales. Rarely flowers.

Common Name: Fame Flower, Flame Flower, Rock Pink

Fame flower, flame flower, or rock pink, is a Midwestern native succulent. Ideally suited to western rock gardens, short fleshy narrow leaves emerge in late spring, followed by wiry stems where tiny rose/pink flowers open up each afternoon. In fall, the top foliage dies off and the plant heads underground for the winter. Because of it's unusual nature, it can be tucked in anywhere at the front of a border, just don't forget where you've planted it when doing spring cleanup. Reseeds slightly.

Phemeranthus calycinum was formerly known as Talinum calycinum.

Common Name: Curl Leaf Mountain Mahogany

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.

Common Name: Shrub Live Oak, Holly Oak

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.

Common Name: Buckwheat, Golden Sulfur-flower

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.

Common Name: Hollyhock

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.

Common Name: Narrow Leaf Purple Coneflower, Black Samson

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.

Common Name: Bearded Iris, Hybrid Cultivars

Distinctive flat, thin upright leaves with flowers arising from the stem.

Common Name: Mersea Yellow Pineleaf Penstemon

‘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.

Common Name: Texas Pink Skullcap, Cherry Skullcap

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.

Common Name: Prairie zinnia, plains zinnia, desert zinnia, mountain zinnia

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!

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