As summer arrives, gardeners seek out those plants that, despite day after day of scorching heat to come, will bloom without interruption for the next several months.
One of the best summer bloomers for Valley gardens is Pentas lanceolata, which develops into a 4-by-4-foot shrub. Its star-shaped flowers are available in red, pink, lilac and white.
Pentas have above-average water needs so a layer of mulch around them, two to three inches thick, will cut down on the frequency of irrigation. A mulch keeps the water in the ground so it can be utilized by roots.
Another all-summer bloomer is the gerbera daisy (Gerbera jamesonii). Gerbera flowers grow up to 5 inches across on long stems and appear in flaming tones of red, pink, yellow and orange. They are highly susceptible to mildew, crown rot, chlorosis (leaf-yellowing) and mollusk attack, so plant them in fast-draining soil slightly above grade, apply a slow-release fertilizer that contains iron and sprinkle snail bait around them.
Plant gerberas in plenty of sun and allow the soil to go bone dry between waterings. Under ideal growing conditions, gerbera daisies will spread out into 2-foot-diameter clumps and persist in the garden for several years. Gerbera flowers are famous for being cut and floated in clear glass bowls as table centerpieces.
Scarlet sage (Salvia splendens) flowers in either full- or half-day sun and blooms throughout the summer. A classic planting scheme surrounds a bed of scarlet sage with either white alyssum or, for maximum brilliance, yellow nugget marigolds. For the red, white and blue look, mix blue mealy-cup sage (Salvia farinacea) with the scarlet sage and alyssum.
Coreopsis grandiflora is a yellow-orange perennial that grows with weedlike profusion in every type of soil. Coreopsis evokes the carefree English garden look and contrasts well with prim and defined bedding begonias, which also bloom all summer long.
Only in recent years have I come to appreciate the nonstop summer flowering of hydrangeas and fuchsias in partial sun exposures. The key to these plants is to situate them where they get enough light to flower. In the Valley, we tend to err on the side of too much shade where these plants are concerned. It is true that the fancier fuchsia varieties are invariably discovered and destroyed by gall mites about two years after planting; in the meantime, though, you should have an eye-popping flower display.
One of the lesser-known perennials for the summer flower garden is the South African cape fuchsia (Phygelius), which blooms heavily in orange, red, pink and burgundy and is pest- and disease-free.
Mexican evening primrose (Oenothera speciosa) is a sun-loving perennial ground cover that blooms best as the weather gets hot. Flowers are pink, cup-shaped and captivating. It is the ideal ground cover for out-of-the-way marginal areas or slopes, where color is desired without excessive watering or maintenance.
TIP OF THE WEEK: Petunias and marigolds can quickly grow leggy in warm weather. Do not hesitate to cut them back by one-half to two-thirds; they will grow and flower again. Cut them back at four- to six-week intervals during the summer, but make sure they are fed with slow-release fertilizer so they will push out new growth soon after being pruned.