By Lindsay Bond Totten
Scripps Howard News Service
Think outside the box when considering the palette of summer-flowering bulbs. The bulbs certainly do. Should we expect less of the gardeners who grow them?
Unlike their spring-flowering counterparts, which are mostly true bulbs, summer-flowering bulbs come in all shapes and sizes. Our spades may turn up a tuber, a tuberous root, a tuberous stem, a corm, a true bulb or a rhizome. Botanists frown at our cavalier disregard for the science of it all, but gardeners don't really care. To us they're called "bulbs," and it's the end result that matters, not their anatomical correctness.
Consider dahlias, for instance. Their roots are about as different from a true bulb — think of a tulip bulb — as a swollen underground root can be. Clumps of fleshy light brown tubers are attached in the middle by last season's thick woody stem. New shoots grow from "eyes" at the base of that stem.
By season's end, a huge bush with eye-popping blooms can result from a single eye attached to a single thumb-sized tuber.
Summer-flowering bulbs are enjoying enormous popularity, and dahlias are leading the charge. Demand for dahlia tubers is up 40 percent from just five years ago, which means lots of gardeners are trying them for the first time.
Most dramatic are the giant dahlias, six feet or more, with dinner-plate sized blossoms. Near-black foliage with contrasting orange or red flowers fuels the urge within us to explore the forbidden side of the color wheel.
In calla lilies, another summer-flowering bulb, it is thick underground rhizomes, which give rise to exquisite chalice-shaped blossoms. These exotic, tropical-looking beauties bloom for a month or longer in mid summer.
To extend the color, start calla lily bulbs two weeks apart and transplant them at intervals into the garden. Or, just support the spent flowers with thin bamboo stakes and enjoy the beauty of their elegant shape long after the color has faded.
Calla lilies also make excellent container specimens. Use one called 'Black Forest', with its satiny near-black flowers, in place of a dracaena spike as the focus of a dramatic combination in a tall, classic urn. 'Pink Giant' is a bit gentler, with soft pink flowers on strong tall stems.
As a gardener, I don't mind in the least that some of these summer-flowering imposters aren't true bulbs. Most true bulbs have an annoying habit of losing their leaves after they bloom. Rhizomes and tubers must be made of sterner stuff, because the gorgeous foliage resists heat stroke and becomes more beautiful as the season wears on.
If a big gap opens up somewhere, I suggest filling it with the wildly satisfying foliage of cannas. Growing from thick, fleshy structures called "stem tubers," new growth starts from nodes, or "eyes," that arise at the base of old stems.
Not shy about asserting its presence, this bold summer-flowering bulb stands politely at three feet, if you select a dwarf canna variety, or towers to more than twice that by season's end if you don't.
The dramatic zebra-striped foliage of 'Bengal Tiger', and 'Tropicanna' means not having to apologize for discreetly snipping off the "offensive" screaming orange blossoms if you can't abide that color in your garden.
Even in the shade, summer-flowering bulbs can assert a spectacular presence. Lovely blooms in rich vibrant shades make tuberous begonias a good choice for brightening up a container or border. I'm particularly fond of the new strain of "lace" begonias ('Pink Lace,' 'Salmon Lace,' 'Red Lace' and 'Apricot Lace'), which have a delicate picotee edge to each petal.
Long used to relying on foliage and texture in lieu of bright color, shade gardeners will appreciate the tuberous begonia's handsome foliage. The bonus, of course, is that they really do bloom in the shade. Make sure to set the "bulb" (actually tuber-corms) very shallowly in the soil, with the hollow side up, so the roots won't rot.
A corm might be the closest thing there to resembling a true bulb without actually being one. Gorgeous gladiolus spikes grown from corms. I find them rather difficult to use in the border, because their foliage does a disappearing act (in this respect corms also behave like bulbs). But as a cut flower, the gladiolus is unequaled, and I devote a generous section of my cutting garden exclusively to their cultivation each summer. A grid of stakes and string helps support the bloom spikes so the stems stay straight and perfect for cutting.
Of the most popular summer-flowering bulbs, only the lily can lay legitimate claim to the title. Curiously, lily bulbs don't really resemble other true bulbs very much. Succulent, overlapping scales, loosely connected to a basal root, must be handled gently so as not to be damaged during planting. But when the flowers (!) and foliage appear, there's no doubt of their sincerity.
Summer-flowering bulbs give gardeners a way to paint the garden with color, from the time the spring-blooming bulbs leave off all the way through fall. An array of summer lovelies awaits the gardener who is willing to accept summer-flowering bulbs on their own terms.
(Lindsay Bond Totten, a horticulturist, writes about gardening for Scripps Howard News Service.)
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