In Los Angeles, summer-flowering bulbs have a distinct advantage over spring flowering bulbs; nearly all summer bloomers come back year after year whereas spring bloomers – including tulip, hyacinth, Dutch iris, and most daffodils – flower for one or two, or possibly three springs, before they vanish from the garden without a trace.
In Los Angeles, the most earnest flowering bulb plant is society garlic (Tulbaghia violacea), which may be planted from containers at any time of the year and is highly popular as a ground cover. Two types are commonly planted, both with violet blooms. The standard type has shiny, slender green leaves and the variegated version has green and white striped foliage. The downside of maintaining this plant is removal of the spent flowers which, unless they are painstakingly snipped off, remain attached for months on end in the form of floppy brown strands. There is an efficient way around this problem, however. When the quantity of faded flowers has given a stale look to the normally fresh-looking society garlic, simply shear the plant to the ground. It will be grateful for the brief rest you have given it before it regroups, refoliates and starts flowering again. And if you are in search of a non-garlicky society garlic, select sweet garlic (Tulbaghia fragrans) instead. Be aware that sweet garlic is less vigorous than society garlic and is more useful as a “one among many” different selections for an English garden, as opposed to being used by itself as a mass ground cover planting.
Another championship bulb-type plant is the calla lily (Zantedeschia aethiopica), that shade lover with the arrow-shaped leaves and the curvaceous, chalice-shaped white spathes. I never cease to marvel at the fact that calla spathes – OK, most people call them flowers, even though they are modified leaves, the actual flowers being the yellow columns or spadixes within – cost several dollars a piece at the florist’s shop. There is no easier plant to grow in the shade than calla lily. It deals admirably with a wide variety of soils, including clay, and will put forth those white spathes for at least four months as long as the old spathes are detached the moment they start to fade or fall over. More gardeners should be familiar with the “Green Goddess” calla cultivar. “Green Goddess” spathes are white at the base, gradually changing to green at the tip.
The pure white and “Green Goddess” callas are robust rhizomatous plants that come back year after year and, given half a chance, will spread throughout the shade garden. These callas should not be confused with the far more delicate red, pink, orange and yellow spathed cultivars that bloom exactly once and are never heard from again.
A summer bloomer for sun or shade is Babiana, the baboon flower. This plant was given its common name in honor of the baboons which, on the African continent, dig up and feast on Babiana corms – bulblike structures also found on gladiolus.
Corms of gladiolus, the most glamorous of summer-flowering herbaceous perennials, can be planted at virtually any time of the year in our area. For continuous bloom, space their planting over several months. Gladiolus requires a fast-draining sandy soil and regular water to bloom its best. To keep plants blooming year after year, their corms must be taken out of the ground each winter and refrigerated for two months. Throw away old corms and dust the new corms with an insecticide that controls thrips, a sucking insect that disfigures gladiolus flowers and causes silver streaking on leaves. Gladiolus is also susceptible to viruses found in vegetable crops such as cucumber, squash, melon, bean and tomato. Aphids that visit infected vegetables will transfer their viral diseases to any nearby susceptible plant, so put distance between your gladiolus and your vegetable garden.
My personal favorite summer-blooming bulbs – well, they actually come from tubers – are the giant dahlias of central Mexico, which can grow up to 20 feet tall with blooms that are eight inches wide. Store tubers in sand or vermiculite, in the refrigerator, during winter.