It is a challenge to get through a North Central Texas summer. Throughout the United States we are being faced with ever-changing climates, and Texas has been no exception. Residents have experienced an usually long spring with heavy rainfall followed by high levels of humidity. Once spring was over, summer came with a pow! For the past several months, we have been at our “normal” daily average of 100 degrees or more with above-average humidity. We have high expectations for our plant material in the South, and this list supports that there are what we call “FlameProof” plants out there. These plants are true Texas summer survivors. All photos were taken at the Dallas Arboretum in August, and they demonstrate that these plants can thrive in this inferno.
Allium x hybrid ‘Millenium’ from Walters Gardens
Hardiness: Zone 5
This Allium stands at 15 inches tall with dark green, glossy foliage that is quick to emerge in the spring. ‘Millenium’ boasts an abundance of large, purple blooms beginning in early summer and lasting through mid-August. We don’t see tip burn on ‘Millenium’ like we see in most Allium mid-summer; the thickness of the leaf helps. ‘Millenium’ has perfect uniformity, creating small clumps of foliage. For years now ‘Millenium’ has shown that it can stand up to Texas heat and continue to thrive. Allium ‘Millenium’ is an ideal plant for the front of a perennial border.
Artemisia arbotanum ‘Cola Plant’ from Hishtil
Hardiness: Zone 8
If you are looking for a small shrub that withstands extreme heat ‘Cola Plant’ is a must. With delicate silver foliage and a compact habit, this plant pops in the landscape. The slight aroma and culinary potential are an added bonus. Even though ‘Cola Plant’ does not bloom, it will bring plenty of color into the landscape with its eye-catching silver hue. Unlike other Artemisia, ‘Cola Plant’ does not spread and overtake in the landscape. Artemisia is a true example of why foliage rocks.
Caryopteris clandonensis ‘Blue Fountain’ from Proven Winners
Hardiness: Zone 7
Plants like Caryopteris ‘Blue Fountain’ are the reason I (Jenny) love plant trials. When I received this a few years ago, I was sure that before summer’s end it would melt in the heat. Well, I was wrong! ‘Blue Fountain’ is one of the highlights in our perennial trial garden. ‘Blue Fountain’ is a robust plant with mild green serrated leaves. It is covered in blue-purple whorls of flowers that encircle the stem. Bees and butterflies flock to ‘Blue Fountain’ just like our arboretum guests.
Convolvulus cneorum ‘White’ from Jaldety
Hardiness: Half hardy (min 23 degrees Fahrenheit / -5 degrees Celsius)
We have had Convolvulus ‘White’ in our container trials for two years now and it has survived a wide range of temperatures with ease. This evergreen sprawling shrub boasts silver foliage and can be maintained with little effort. There are white blooms that appear in early spring, but the main selling point is the gorgeous foliage that can easily be mixed into any landscape. With its natural trailing ability, Convolvulus ‘White’ is perfect for containers or hanging baskets.
Scaevola ‘Surdiva’ series from Suntory Flowers
I have written about the Scaevola ‘Surdiva’ series time and time again and will continue to. It is a must-have in any region where high summer temperatures are a factor. The Scaevola ‘Surdiva’ series offers a low growing mat of color all summer long. Colors in the series are blue, pink and white. ‘Surdiva’ is quick to fill in an area, whether in-ground or in a hanging basket. Floral coverage and vigor are uniform throughout the series.
Catharanthus roseus ‘Titan Romance Mix’ from PanAmerican Seed
It was a rough year for Catharanthus due to frequent, heavy rainfall at the beginning of the summer and it quickly became evident which varieties had the greatest disease resistance. ‘Titan Romance Mix’ was one of these varieties. It is vigorous and consistently offers an abundance of blooms ranging from white to light pink and dark pink. Tight mounds of color made this vinca stand out. Rain or shine ‘Titan Romance Mix’ did not care!
Portulaca oleracea Soleil Fuchsia Pink and Tangerine from EuroAmerican
Portulaca is quick to come to mind when creating a list of drought-tolerant plants. Soleil is a reliable series with good vigor, an upright habit and large flower size. Fuchsia Pink and Tangerine were the two standouts, offering consistent blooms in bright, vivid colors all summer. Even with the heavy spring rains Soleil still bloomed and performed well, making it one of the best series we have trialed. Portulaca is a must-have for any Texas gardener in summer.
Ricinus communis ‘Red Giant’ from American Takii
It is evident where ‘Red Giant’ gets its name. ‘Red Giant’ stands more than 6 feet tall with large, dark purple foliage. It is a great addition to a sunny landscape bed where you are looking for height and texture. Bright pink blooms are present mid-summer. Ricinus can be a forgotten plant when we are talking about tough plants, but it proves itself year after year. Be aware that Ricinus is poisonous, so plant it in a location that is out of reach and always wear gloves when handling seeds.
Lantana Landscape ‘Bandana’ series from Syngenta Flowers
Hardiness: Zones 8-11
Perennial (trialed as an annual)
This is a new addition to the ‘Bandana’ line of lantana from Syngenta Flowers. These plants establish quickly with a trailing habit that will quickly fill a landscape bed or container. Four colors are available (gold, pink, red and yellow) and all have shown great blooming ability, but pink is the most vigorous. What makes the ‘Bandana’ series stand out is its controlled vigor where other lantana tend to be overly aggressive. Then there are Lantana on the market that just do not get big enough. It is like the Three Bears, ‘Bandana’ series is just right!
Cuphea ‘Vermillionaire’ from Proven Winners
Cuphea ‘Vermillionaire’ was introduced at the 2014 California Spring Trials and is a great addition for Southern gardeners. ‘Vermillionaire’ is the summer answer for mixed containers with its dark green foliage and bright orange flowers that are a perfect contrast. This Cuphea stood up to our crazy summer with ease, blooming constantly.
Gomphrena ‘Pinball’ series from Sakata
Gomphrena is another plant at the top of the annual plant list for drought tolerance. ‘Pinball’ has a compact habit that makes it ideal for landscape and container planting. Three colors are available: purple, Snow Tip Lavender and white. With a maximum height of 2 feet it pairs well when planted alongside other annual material. Unlike other cultivars, ‘Pinball’ is nice and controlled and doesn’t overwhelm a landscape.
Salvia hybrid ‘Amistad’ from Jaldety
Hardiness: Zone 8
Salvia ‘Amistad’ has been one of my favorite introductions during the last few years. ‘Amistad’ is a medium sized, semi-evergreen shrub that stands 4 feet tall and blooms all summer long. Blue-purple flowers shout summer and deep purple, almost black bracts really highlight ‘Amistad.’ Plant in full sun and cut back in early summer for an even better show of flowers. An added bonus is that butterflies swarm to ‘Amistad.’
Sedum hybrid ‘Maestro’ from Proven Winners
Hardiness: Zone 3a-9b
Here in Dallas, we can have problems growing sedum because of our heavy clay soils. ‘Maestro,’ however, does not seem to mind. This beefy sedum is quick to come out of dormancy and maintains a tight habit while other varieties tend to lodge. ‘Maestro’ has large leaves with a tinge of purple that are complemented by the large pink flower heads that appear in late summer.
Cephalotaxus harringtonia ‘Hedgehog’ from Iseli Nursery
Hardiness: Zone 6
When we talk about drought tolerant plants, we tend to forget about the shade. Cephalotaxus ‘Hedgehog’ is the model plant for any shade garden. ‘Hedgehog’ is a dense dark green leafed evergreen that stands at 2 to 2.5 feet tall. Little to no upkeep is required, and it brings a woodlands feel to any shade garden. Plant and walk away!
Jenny Wegley is the director of horticulture and Kaylee Decker is the trials manager at Dallas Arboretum in Texas.
Photos courtesy of Dallas Arboretum