Valley Gardeners Turn to Heat-Loving Plants
Summer’s heat has settled over Southern California’s valleys like a suffocating blanket. Adapting to life away from the gentle influence of the ocean, a sturdy yet sybaritic breed of gardeners has evolved in the heat of Ojai and Simi, Azusa and Cucamonga.
By learning to concentrate on plants that thrive in high summer heat, they have given up none of the pleasures of gardening, only some of the pain. The biggest pain they avoid is trying to nurse heat-hating plants through the soaring temperatures of summer and fall.
During the long afternoons of summer, valley gardeners lounge in the shade of native oaks and Peruvian pepper trees while all around them the garden is a riot of carefree color. Reveling in the torrid sun, hot-hued bougainvilleas, oleanders and crape myrtles are cooled down only by the blue blossoms of plumbagos and chaste trees.
Patios are shaded by grapevine-covered arbors or artfully pruned olive trees and are scented by gardenias and oleanders. In the fall when the Santa Ana winds are screeching down from the passes and the mercury rises above 110 degrees, those who have come to terms with their climate simply watch the pomegranates ripening.
Some of these plants, including grapes, pomegranates and olives, have been cultivated so long they’re mentioned in the Bible, but others are the latest introductions from around the world. Some heat-lovers need a lot of water to stand up to our summers, while many are drought-tolerant. They all can be planted now but they will need to be watered carefully to get them started.
One newcomer that has proven itself under the most trying conditions is Canary Island sage (Salvia canariensis). In a field test of drought tolerance at UC Riverside Botanic Garden, this shrub survived an entire summer in good shape with no irrigation at all.
It blooms in late spring and summer with flower spikes rising six feet tall above the gray-green arrowhead-shaped leaves. The flowers are lavender, but much of the shrub’s color comes from the conspicuous wine-colored bracts surrounding the flowers. Canary Island sage makes a good companion for statice, chaste tree and buddleias in the water-conserving garden.
Chitalpa ‘Pink Dawn’ is more than a new introduction for hot areas--it’s a completely new creation, the hybrid offspring of our native desert willow and the catalpa tree from the southeastern United States. Adding to its mystique is the fact it was hybridized in Uzbekistan in what then was the Soviet Union. ‘Pink Dawn’ is useful as a fast-growing patio tree or multi-trunked shrub that bears clusters of light pink trumpet-shaped flowers in summer. It doesn’t have the brilliant colors of crape myrtle but is much faster than that old stand-by.
Crape myrtles, too, have been going through some changes. The latest in the ‘Indian tribe’ series developed at the U.S. National Arboretum are in nurseries now. Pink-flowered ‘Pecos’ and ‘Zuni’, with deep lavender blooms, are hybrids with several characteristics that set them apart from older crape myrtles--larger, deeper green leaves, mahogany-red bark and the best resistance to mildew of any crape myrtle so far. Powdery mildew, a fungal disease, discourages the use of crape myrtles in coastal areas, but is also a problem in the valleys, especially after a wet winter.
Because the list of truly heat-loving plants is a fairly short one, valley gardeners are always on the lookout for new versions of old, tried-and-true friends or new ways to use familiar plants, according to landscape architect Eric M. Lesser of Studio City. He likes to plant dwarf myrtle (Myrtus communis ‘Compacta’), mostly used for formal clipped hedges, as unsheared foundation shrubs or as a lightly pruned natural-looking hedge. Treated this way, dwarf myrtle bears fragrant white flowers in summer that would otherwise be nipped in the bud.
Other useful plants that Lesser feels are under-appreciated for their good heat tolerance are the climbing yellow Lady Banks’ rose, the Chinese pistache tree, and, for edging and small-scale ground cover, blue sheep fescue.
A beautiful gardenia that has been grown for years in Florida and Hawaii under a variety of names has been rechristened ‘First Love’ and is now in Southern California nurseries in quantity for the first time this summer.
Audrey Teasdale, botanist at Monrovia Nursery, predicts gardeners will find ‘First Love’ an improvement over the popular ‘Mystery’ gardenia in all seasons, with heavier bloom in the warm months, and larger, extremely glossy leaves that stay green in winter rather than yellowing.
A new dwarf bougainvillea for ground cover or hanging baskets has been discovered on the grounds of California State Polytechnic University, Pomona, and is being grown by Colorama Wholesale Nursery in Azusa. This plant is apparently a sport, or mutation, of another bougainvillea variety, but it displays an entirely new combination of pink flower bracts and leaves edged with a broad band of yellow. Its rather misleading name is ‘Orange Ice’ because the new bracts are orange before they expand and turn rose pink at maturity.
More improved heat-lovers to look for this summer are a deep purple Geraldton wax flower (Chamelaucium ‘University’) from the UC Santa Cruz Arboretum; a stunning white and red Rose of Sharon (Hibiscus syriacus ‘Helene’) introduced by the National Arboretum; and a richer blue Cape plumbago (Plumbago ‘Royal Cape’) that is the creation of veteran plant-breeder Paul L. Scott of Duarte.
