USDA Hardiness Zone 6

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

Other Cold Hardiness categories

Common Name: Columbine

Many Aquilegia’s are native to the U.S. Golden columbine, Aquilegia chrysantha is a Texas and southwest native, has yellow flowers and can take more sun than some varieties. McKana's Giant is the hybrid columbine most often sold. Large beautiful bi-colored flowers dazzle in woodland and shady area. Rocky Mountain columbine, Aquelegia caerulea; and wild columbine, A. canadensis, are other common columbines. Rocky Mountain columbine is the state flower of Colorado.

Common Name: Larkspur

The old fashioned larkspur is a drought tolerant reseeding annual, previously associated with delphiniums (now in the Ranunculaceae family). I’ve grown it in my alley, in the xeristrip, and its crept into my medium water-use zone. Deadheading keeps millions of tiny seeds from overcoming your garden next year, and also keeps the blooms coming. Larkspur can flower for six weeks. Again, deadheading is important to prevent a massive infestation throughout your landscape.

Common Name: Coral bells, Alum root

Heucheras are native to the North American continent and make wonderful foliage and flower plants for your woodland border. Grown mostly for its interesting, evergreen foliage, coral bells will continue to flower on mature plants if kept deadheaded into the summer. Although the native heucheras are great in themselves, there are hundreds of hybrid cultivars to choose from.

Common Name: Cascading Ornamental Oregano, Lebanese Oregano, Hop Oregano

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.

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: Woolly Creeping Speedwell

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. 

Common Name: Scarlet globemallow

Scarlet globemallow is a welcome addition to any xeric or High Desert garden. Small coral flowers bloom from May (sometimes April) through into the fall. Although scarlet globemallow will survive with no additional moisture in our climate, once a month watering insures steady blooms. The plant is similar in appearance to S. ambigua, which can bloom coral, white, lavender and pink.

Common Name: Cactus

Not all succulents are cacti, but all cacti are succulents. Nearly alll cactus species are native to the Americas, providing a prickly evergreen presence. There are many cactus that are cold hardy for the Texas Panhandle. There might be one for your garden.

Common Name: Bigelow's Tansyaster

Bigelow's tansyaster is easy to confuse with Tahoka daisy but is not as showy. Bigelow's aster is a fall blooming biennial, with far fewer purple rays and a smaller, yellow brown center disk. It populates plains in Colorado, Arizona and New Mexico. In the fall, whole fields will wear a purple haze due to this tansyaster.

Common Name: Prairie Dropseed

Prairie dropseed is smaller than both alkali or giant sacaton, more fitting for the city garden. A warm season bunch grass, prairie dropseed is a most attractive low or medium water-use grass with graceful green foliage. The seed heads emerge in late summer into fall with light pink seeds, that is said to naturalize some, but not invasively. A slow grower. Foliage turns a pleasing golden orange in the fall. Native throughout the Great Plains, including Texas. Tolerates most soil conditions.

Common Name: Littleleaf Mockoragne

Littleleaf mockorange is native throughout the foothills, dry rocky slopes and open woodlands from 4000 to 8000' in the Southwest usually growing to only 4 feet. This native mockorange is similar in form to the European import, they are fragrant, but not of orange. Attractive white, 4 petaled flowers bloom in early summer, small slightly glossy green leaves. Coldy hardy, heat and drought tolerant.

Common Name: Hyacinths

Hyacinths are a much loved and very fragrant spring bulb, flowering in March and early April in our area. Clusters of bell-like flowers dangle from a central stem.  Native to Asia, hyacinths were one of the early favored flowers by the Persians, Turks and Europeans, in fact, practically everyone who came in contact with them. Easy to grow in full sun to part shade in average garden soil. Hyacinths come in many pastel colors, both single and double flowers.

Common Name: Bear's Breeches

An old world Mediterranean plant best known for the acanthus leaf shape used as a basis in classical Greek and Roman designs. The plant itself takes 2 – 3 years growth before flowering. Attractive flowers with purple bracts on tall spikes to 4’. Frost sensitive, will die back in a late spring frost, but will come back. Adds architectural and textural interest.

Common Name: Yellow Corydalis

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.

Common Name: Diana Rose of Sharon, Althea

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.

Common Name: Rock Rose, Rose Mallow Pavonia

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.

Common Name: May Night Meadow Sage

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.

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: Desert globemallow

Desert globemallow is one of those native plants that keeps on giving, asking so little in return and is a worthy addition to any native or xeric garden. Typically, desert globemallow sports pretty pink flowers. though some plants will bloom white, coral or lavender. Whatever color, they are worth the addition to your sunny and dry landscape for their pleasant cheery nature. Similar to appearane to S. coccinea, a coral blooming species.

Common Name: Bee Balm

An American native requiring medium to high water, it is a prolific grower, an old fashion pass-along plant. Perfect for a mixed border or at the edge of the vegetable garden to attract bees. The variety shown is most likely 'Violet Queen', although I'm unsure. However, it is not the common scarlet bee balm or red bergamot, that also grows well here. Blooms throught the summer and is an attractive addition.

Common Name: Virginia Creeper Vine

Virginia creeper, one of our pernicious native creepers, is a worthy low care vine for brilliant fall foliage and deep blue berries (highly toxic to humans) loved by birds. Virginia creeper normally spread by seeds in bird droppings, which is the method it came to my landscape. When spotted early, Virginia creeper easily pulls out, but if not spotted, within no time, it will cover a fence, climb a pole or cover an area. Which can be either a good thing or a bad thing, depending on one's view.

Common Name: Utah Serviceberry

Utah serviceberry is a quite beautiful shrub extending from the Southwestern states northward throughout the Rocky Mountains and through various ecosystems between 4000 and 8000 ft in elevation. Deep green leaves, large oval shaped and toothed at the margins, many intricately branched, smooth gray to maroon bark. Large white flowers with five widely spaced petals open in May and June. Berries appear in the summer, ripening to pink, then red, then finally dark blue. Leaves turn red and orange in the fall.

Common Name: Western Sand Cherry

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).

Common Name: Coral Bells, H. sanguinea, Alum root

Common Name: Greek yarrow

Small green gray evergreen leaves forms mounded, low growing xeric plant with small white flowers in late spring. Does not spread vigorously. Easily propagated by root cuttings. An alpine from the Balkans region.

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