USDA Hardiness Zone 6

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

Other Cold Hardiness categories

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: Century Plant

Agaves are striking and architectural Southwest native plants and are included in a group of plants I term Southwest evergreens. They are unusual in that at maturity, they only flower once, and then die. for this reason, some classify them as multiannual, rather than perennial. However, as they common name suggests, it takes many years before they flower. Leaves of the Agave are arranged in a spiral beginning from a near invisible stem, forming a rosette.Agaves vary in size from 4-6 inches to larger than man-size.

Common Name: Tansy Aster, Tahoka Daisy

Tansy aster is an annual native to the Southwest and throughout the Plains even into Canada. Fernlike, or tansy-like (tannacetifolia) light green foliage with beautiful aster-like lavender flowers with yellow disks about 1 1/2 to 2 inches across. Blooms from late spring through fall. A once a month watering will keep the blooms coming throughout the summer. It will keep its compact shape in lean, poor soil but will become much larger in well amended soil. Minimal amending is recommended. Tansy aster is another example of our natives plants giving so much, asking so little in return.

Common Name: Giant Sacaton

Giant sacaton is one of the largest bunch grasses native to the Southwest, like alkali sacaton on steroids. Seems to thrive in poor soils with no supplemental irrigation. It will grow even bigger with added moisture. Thick textured grass blades, it will rival pampas grass for size and beauty, although it plumes are near as showy, giant sacaton has a flowing fountain appearance. A warm season grass, it is cold hardy and thrives in sun and heat.

Common Name: Beargrass, Sacahuista

Bear grass is similar in appearance to yucca and clumping grass, but is neither. Usually found growing in high desert areas, along cliffs and rocky slopes. Thin succulent grasslike yellow-green leaves emerge from a trunkless center, are pointed and sharp edged. A plume-like inflorescence with many tiny cream colored flowers emerges early summer. Cold hardy, drought and heat tolerant.

Common Name: Mohave Sage

Beautiful xeric sage with aromatic soft gray green leaves, mostly evergreen. Summer to fall blooming with mauve/purple sticky but fragrant flowers. Takes a few years to reach mature height. Requires good drainage and dry soil in the winter. A Plant Select® Plant. Native to California and will grow in the High Desert regions. Cold hardy to Zone 5 and quite heat tolerant.

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: 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: 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.

Common Name: Dianthus 'Bath's Pink'

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.

Common Name: Standing cypress.

Reseeding biennial, native to Texas, and the southeastern US. The red tubular flowers make it attractive to hummingbirds. The upright stalks are brittle and break off easily.

Standing cypress will flower the first year, and may, or may not come back a second year, but you should see some seedlings. Transplant those. The glossy green foliage to the right in this picture belongs to Anisacanthus quadrifidus wrightii, flame acanthus.


Common Name: Red Rocks Penstemon, Red Rocks beardstongue

‘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.

Common Name: Plumosa, or Plum Meadow Sage

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.


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