Some plants like it hot – and not just cactus.
Summer officially began this week, but the hot temperatures have already given us a taste of the scorching days to come. We can retreat into air-conditioned indoor bliss – or at least under a shady tree. Our gardens aren’t so lucky.
When it comes to Sacramento’s sizzling summers, “full sun” can feel like a blast furnace to such tender plants as peppers, hydrangeas and roses. But some perennials and native grasses actually relish that high intensity heat. It’s just like home.
“In Sacramento, you want plants that can take the heat,” said chief horticulturist David Salman of High Country Gardens, a major online source for water-wise and native plants. “It’s really important for people to think about it, especially in areas prone to drought.
“I recommend for folks in California native plants, but not typically plants native to California,” he added.
During warm summer months, many California natives tend to turn brown and go dormant, especially in the Central Valley.
“But that’s the time of year people want to be outside and enjoying their gardens,” Salman noted. “They want summer, late summer and fall color.”
That summer color is not necessarily the “California gold,” tan or brown that became so familiar during four years of drought.
Instead, Salman looks to another arid American region.
“For summer color and heat tolerance, I recommend plants native to the Chihuahuan Desert of West Texas and New Mexico,” he said. “I like them for several reasons. They’re very heat tolerant, but they’re also very cold tolerant. They can take temperatures down to 0 degrees. Plants native to the Sonoran Desert (of Arizona and Southern California) don’t have nearly as much cold tolerance.”
While their California cousins may be sleeping through the summer, Chihuahuan natives have evolved to bloom during the hottest months – if they have water.
“Without much extra water, these plants will flower over the summer and well into fall months,” Salman said. “There’s wide applicability for these Chihuahuan plants. They’re native to Texas but they work all over.”
These Texas transplants are proven to succeed in the Greater Sacramento area. Many have been tested in the UC Davis Arboretum’s low-water gardens, where they receive irrigation only twice a month – or less. They bloom and look gorgeous, even after triple-digit days in May and June.
Ellen Zagory, the arboretum’s public horticulture director, particularly likes summer bloomers that do double duty, attracting beneficial insects and birds.
“My current favorite plants for our hot summer gardens are things that will attract lots of California native bee species and plants that attract hummingbirds,” Zagory said. “I think every sunny garden should have a California fuchsia, which comes in many sizes and is a magnet for hummingbirds. For bees, Solidago californica (goldenrod) is a magnet. It provides both pollen and nectar for many small butterflies and is tough as nails. Both these should be only in low to very low water areas because they can spread.”
If watered two or three times a week, California fuchsia and goldenrod can grow very large very quickly, she explained. They prefer heat on the dry side.
Besides the California fuchsia and goldenrod, also blooming in the arboretum’s Ruth Risdon Storer Garden of water-wise plants are two standout Texans – desert willow (Chilopsis) and Texas ranger (Leucophyllum langmaniae).
“I love desert willow,” Salman said. “It’s called a willow because of its narrow leaves, but it’s actually a member of the catalpa family and has these beautiful pink to purple flowers. I’m particularly fond of the new seedless varieties such as Monrovia’s Timeless Beauty. They love the heat but can take the cold.”
Desert willow, which grows into a small tree up to 20 feet tall, is native to both the Sonoran and Chihuahuan deserts. Seedless varieties are preferred for home gardens; otherwise, little desert willows will pop up all over.
“Art’s Seedless desert willow is another fantastic tree,” Salman said. “It’s sterile and ever blooming. The more heat, the better. And hummingbirds love it.
“Texas ranger is another excellent example of a heat-loving Texas native that grows well elsewhere,” he added. “The variety Lynn’s Legacy does particularly well in California.”
In Texas, this popular blooming shrub with purple flowers is nicknamed the “barometer bush,” he added. “It blooms in anticipation of rain. Somehow it can feel changes in barometric pressure. When it blooms in summer, you know rain is coming.”
Due to its toughness and low-water needs, Texas ranger has become ubiquitous in Arizona and New Mexico, Salman noted. “It’s in parking lots and (commercial) landscapes all over. But don’t trim them into balls and squares; they trim them like crazy in Arizona into little pillbox shapes. When you don’t trim, you get more flowers for less work.”
Salman is fond of another catalpa relative that’s a favorite in Texas but just beginning to take root in California: Tecoma. Also called common yellow elder or Arizona yellow bells, this small flowering tree offers bowers of fragrant, showy blooms.
Several penstemons and sages from Texas, California and the Southwest do well during Sacramento summers.
“Pineleaf penstemon (or beardtongue) grows all over New Mexico,” Salman said. “It’s an outstanding plant but not really known outside of New Mexico. It’s an evergreen shrub with bright yellow or orange tubular flowers. It’s a beardtongue that deserves more use.”
Heat-loving penstemons are now available in more colors, he noted. “The new Mexicali hybrid penstemons such as Pikes Peak Purple and Red Rocks are fantastic. They have hybrid vigor; they bloom and bloom. But they’re also very drought tolerant. They like a deep soaking, but only occasionally.”
Sages have long been a favorite in sunny low-water gardens. Salman recommends autumn sage (Salvia greggii), a Texas native with lipstick red blooms that hummingbirds love, and West Texas willowleaf sage (Salvia reptans), which has dark blue blooms.
“Willowleaf sage is a new salvia that people may not be familiar with,” he said. “Autumn Sapphire just won the Plant Select trials (in Colorado). It has beautiful deep cobalt blue flowers in early fall when it’s still pretty hot. It makes hummingbirds go nuts. It’s an excellent sage for Sacramento.”
Some California sages can handle heat, too.
“A great California sage for Sacramento gardens is Salvia pachyphylla,” Salman said. “It’s nicknamed Mojave sage but that’s actually a misnomer; it’s native to the Southern Sierra. It’s like Salvia dorii (purple sage) on steroids. Its blooms are three times as large, and it’s very cold tolerant, which makes it a great choice for foothill gardens.”
Don’t forget native grasses such as deer grass and blue grama, he added, including his personal favorite, Blonde Ambition (Bouteloua gracilis). Their graceful flower heads dance in the summer breeze.
“There are so many great native grasses,” he said. “They love the heat and still look fabulous.”