USDA Hardiness Zone 6

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

Other Cold Hardiness categories

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: Purple Coneflower

A terrific variety for the prairie garden, though requiring prairie conditions -- good soil with good drainage and more frequent watering than our native, E. angustifolia. Coneflowers are all the rage right now with many new introductions every year, ranging from white, yellow, orange to the popular purple. Most of these should be located in your medium to high water-use area. The richer the soil and with weekly watering (high), you'll enjoy grander blooms. A good border plant in the transition area between turf and medium water-use. E.

Common Name: Silver-edged Horehound

The only draw back to this pretty, silver-edged groundcover is its flowers! If only it didn’t, it would be a perfect no maintenance, no water groundcover for hot, sunny locations. You can see the tiny ball shaped flower heads in the picture, which look rather indistinct. However, after flowering, they turn an ugly shade of brown that mar the beautiful leaves unless you shear them off. Though a creeping groundcover, silver-edged horehound is not invasive like the common horehound, M. vulgare.

Common Name: Russian Sage

Russian sage is a must have shrub for every low water-use landscape. Russian sage is used extensively throughout our southwest landscapes, planted along with Buddleia, Carl Forester Reed Grass, Salvia greggii cultivars, Anisacanthus quadrifidis wrightii and Hesperaloe parviflora. It is hard to beat its use where a long flowering, showy, low care, drought tolerant shrub is needed.

Common Name: Color Guard Yucca

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’.

Common Name: Black and Blue Sage, Anise scented sage

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.

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: 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: 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: White Swan Purple Coneflower

A beautiful white variety of the purple coneflower. This picture doesn't do the flower justice.

Similar to the purple coneflower, this white variety is really a high water-use plant that appreciates afternoon shade. Deadhead to prolong the bloom period, but keep end of season blooms on for fall and winter interest.

Common Name: Blackfoot Daisy

Native wildflower that likes it lean and mean. Over watering and well amended soil will usually cause Blackfoot daisy to die a premature death, even for a short lived perennial, such as it is. It would be an ideal border plant, similar to alyssum, if not for its tendency to move about where it will (that is, die where you plant it and seed somewhere else). Still, it’s worth a try. Our Panhandle xeric gardens should never be without Blackfoot Daisy. In fact, once you plant Blackfoot daisy and let it seed, you should never be without it (and that’s a good thing).

Common Name: Persicaria, Red Dragon, Red Dragon Knotweed

The most remarkable quality of Red Dragon Persicaria is its burgundy red patterned leaves and red stems, a plant grown much more for its foliage than flowers. (The flower stalk in the upper right is of Acanthus spinosus.) Not a native (native to China) it will come back if nipped by a late frost and will suffer sunburn in afternoon sun. Red Dragon may take 3 years before flowering, however, that is not a drawback.

Common Name: Prairie Sun Black-eyed Susan

Rudbeckia is advertised as heat and drought tolerant, but I have not found it so. I’ve found it to require at least weekly watering during the heat of the summer. A shortlived, southern native perennial, it likes the humidity and rain from southern climes. These very large and stunning composites may be worth your effort, just place within the correct hydrozone.

Common Name: Perky Sue, bitterweed

Small but tough is Perky Sue. Woody base with thin short green leaves from which many stems shoot up to display many yellow daisy like flowers from April into fall. Many people know this plant by the genus name Hymenoxys, but has been changed to Tetraneuris in the last decade. There are a few relatives that look quite similar and are all equally valuable in the garden: T. acaulis and T. odorata.

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.

For more information and a list a gray and silver leaved plants, read Fifty Shades of Gray, my most viewed page.

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: Flame acanthus

A native to Texas, flame acanthus loves the heat and full sun! A hummingbird and butterfly plant. Does well in poor soil. May only be cold hardy to Zone 7, however, it has come back for several years in the Panhandle. Grows rapidly and will flower the first year, if you must replant, this is still a good choice for mid to late summer and autumn flowers. Re-seeds some, transplant them early as their roots grow deep.There is another variety with light pumpkin colored flowers, but this one does not bloom as prolificly.

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