The Dallas Arboretum Trial Program takes data on 7,000-plus annuals, perennials, woodies, grasses and trees each year, looking for the toughest of the tough. North Texas is a brutal climate that can swing from one extreme to another; six months of drought is usually followed by a month of flooding. Many of the arboretum’s trials focus on heat tolerance and ability to withstand low water requirements, because Texas is experiencing water restrictions like other states. We highlight some great drought-tolerant contenders here.
Gomphrena ‘Fireworks’ bred by PanAmerican Seed (annual)
This is a beast of plant that you can only truly appreciate once it has grown out. It’s somewhat leggy and sad-looking in nursery containers, but in the landscape this bold plant truly shines. Fuchsia flowers tipped with gold wave on 3-foot-tall stems and mounds of soft textured foliage. Once established, plants can survive easily on lower water use.
Leucophyllum langmaniae ‘Lynn’s Legacy’ (shrub)
Found by the legendary Texas plantsman Lynn Lowery, this evergreen shrub is truly a gift to the garden. Glowing lavender-pink flowers frost soft grey-green foliage off and on from summer until fall. Exceptionally drought-tolerant plants are best in xeric beds, also outstanding in containers. Unlike many other cultivars, this one stays compact and seldom needs shearing, and it is more floriferous.
Ligustrum ‘Sunshine’ by Ball Ornamentals (shrub)
Choirs of landscape architects would be singing the praises of this plant – that is, if they knew about it. Compact, easily trimmed shrubs of pure gold are the perfect contrast for boxwood or barberry in formal garden design. Plants are supposedly sterile and will only reach 5 feet tall in 10 years. This plant can be trimmed to 1 foot in height, and it must be in full sun for best foliage color. It is semi-evergreen in milder climates.
Purslane ‘Cupcake’ and ‘Rio’ series by Dummen and Ball Floraplant, respectively (annual)
You have to love a plant that you can leave unwatered for two weeks while on vacation, then just sprinkle with water when you return and it almost instantly resurrects. These new cultivars really put on the flower power, and the foliage stays tight and compact. They are excellent in hanging baskets, spilling out of containers or growing in that spot by the mailbox where everything else bakes during the summer. The flowers on both of these new cultivars are much larger than many of the older selections.
Evolvulus ‘Blue My Mind’ by Proven Winners (annual)
Who doesn’t like the cooling color of blue in their garden during the infernal heat of July? ‘Blue My Mind’ is a major improvement over the rangy and stingy blooming variety we’ve all been using for years. This new compact variety is also more drought-tolerant and heavier-blooming.
Celosia ‘Intenz’ by Ball Ingenuity (annual)
This plant is not for the faint of heart. These 3-foot-tall plants are crowned with burning spikes of flaming fuchsia. Through the hottest weather that Texas can throw at it, ‘Intenz’ just keeps right on flowering. It took a hard frost to put this one down. For a Celosia, it also has a very nice foliage and habit.
Helichrysum ‘Silver Leaf Yellow’ by Suntory (annual)
Trying to keep a basket watered during a Texas summer is nearly impossible; sooner or later, it’s going to dry out. That’s where ‘Silver Leaf Yellow’ comes in. This soft, flowing carpet of sage-green leaves is punctuated with golden polka dots, and it just laughs at attempts to kill it. Vigorous growth quickly cascades over the hanging baskets to 2 feet.
Catharanthus ‘Cora Cascade Strawberry’ by Goldsmith Seed (annual)
Periwinkles were made for the hot humid south, but the Dallas Arboretum Trial program is ground zero for Aerial Phytopthera. It’s guaranteed that any Vinca the arboretum plants here is going to get a true test of resistance, and most don’t pass.
This new ‘Strawberry’ introduction features soft, creamy, pink flowers with a strawberry-red center that curtain 2 feet over hanging baskets all summer long.
Like all Vinca, this one was drought-tolerant and did not require daily watering to keep alive.
Lantana ‘Lucky Pot of Gold’ by Ball Floraplant (annual)
It’s almost impossible to drive a mile in Texas and not see a planting of Lantana.
Drought, heat and humidity only make this plant grow faster. Not too big and not too small, this 1-foot-tall variety is just right.
Wide balls of burning gold flowers bloom all summer long. As a matter of fact, this variety actually blooms better if you let it get thirsty between watering.
Gaillardia ‘Galya’ series by Danziger (annual)
Flame-like flowers in red, orange, yellow and bicolor come in double and single forms in this new hybrid from Danziger. Bred from the Texas native G. pulchella, this plant relishes heat and drier soils but will also tolerate cool weather and seasonal deluges. Once the weather heats up, this plant never goes out of flower.
Portulaca ‘Samba’ series by Athena Brazil (annual)
A pass-along plant from your grandmother’s time, this Portulaca laughs at dry weather. Broken stems lying on the sidewalk have been known to flower for three weeks before they finally give up. Two-and-a-half-inch flowers of magenta, white or a combination of the two dot the foliage all summer. Plants are only slightly slower than kudzu in their growth habit and will quickly spread to 3 feet either across the ground or out of baskets. Forgot to water for two weeks? No problem, this plant looks just the same.
Hesperaloe ‘Brake Lights’ by Mountain States Wholesale Nursery (perennial)
The plant commonly called false red yucca for years is perplexing: where is the red? Then comes the aptly named ‘Brake Lights,’ which has a true red flower and stems. Drought tolerance is this plant’s middle name. They’ve been seen growing in Arizona with no supplemental irrigation at all, and they’re almost constantly in flower from late spring to fall.
Agave ovatifolia – Whale’s tongue Agave (perennial)
Another plant that Lynn Lowry found in Mexico has quickly become the favorite Agave across the state. These zone 7, hardy, icy-silver plants form large 5-foot rosettes. Unlike many others of this genus, this one does not form pups. Able to withstand drought, hot summers and cool wet weather.
Verbena ‘Princess Blush’ and ‘Princess Dark Lavender’ by Southern Living Plant Collection (perennial)
Many verbenas in the Texas climate quickly succumb to high night temperatures and powdery mildew, but not this one. Both colors of this variety are vigorous plants that flower off and on all summer on mildew-free foliage.
As a matter of fact, the flowers continue right up until a hard freeze finally puts them to slumber for the winter. Mat-forming foliage requires low water to keep flowering.
Thirsty for more? Here are some additional drought-tolerant varieties – provided by their respective companies – that are either already introduced or soon-to-be-introduced to the market.
Touting excellent branching and a strong upright structure, Clio Magenta features dark foliage and long, continuous flowering. This seed-sterile plant also has non-stick leaves and exceptional garden performance.
The Santana series lantana is a semi-trailing structure that is great for ground cover as well as baskets. It features long-lasting, abundant flowering and interesting diversity of color.
Scaevola ‘Blue Haze’ and Scaevola ‘Blue Wind’ are elegant and floriferous low-spreading ground cover plants whose flowers are concentrated in clusters at the edge of the leafy spikes. Suitable for rockeries and borders.
RED FOX Cupcake portulacas performed beautifully at trial sites around the country last summer, one of the hottest on record in many areas.
They loved the tough conditions, showing large, bright-colored flowers in abundance. They feature good branching and controlled growth and are good trailers, making them an excellent choice for landscape and basket applications.
Company note: These plants must be established in the landscape in order to exhibit drought-tolerant qualities. They are not – drought-tolerant from the beginning.
A new GoldFisch Heat Lovers series, Starcluster is bred to perform through summer heat. Its large flower clusters are supported by strong stems to ensure consistent quality and shelf appeal at retail.
A well-branched habit makes Starcluster pentas a showstopper in gallons or larger containers and landscapes. Consumers will appreciate Starcluster for its low-maintenance performance that requires no deadheading as new flowers form over spent blooms. Available in four colors: white, rose, red and lavender.
Sriracha is a totally new, heat-loving series from seed that offers season-extending opportunities for growers and retailers. Available in three colors, Sriracha provides vibrant color from spring through the heat of summer. Sriracha is a faster, cost-effective alternative to specialty vegetative varieties. L&L
Turner is senior director of gardens at the Dallas Arboretum. Wegley is senior manager of trials and greenhouse at the Dallas Arboretum.
Unless indicated, all photos courtesy of Dallas Arboretum & Botanical Gardens
Lynn’s Legacy : Courtesy of George Hull
Danziger varieties: Courtesy of Danziger / red fox cupcake: Courtesy of Dummen / SAKATA VARIETIES: courtesy Sakata