Summer's show-off bulbs - recommended flowering plants include acidanthera, calla, dahlia, gladiolus, lily, Mexican shell flower, tuberose, and tuberous begonia; growing tips are included

Sunset, Spring, 1997 by Dick Bushnell

8 exuberant plants with blooms to brag about

It is a wondrous horticultural paradox that such stunning floral beauty can spring out of such a gnarled-looking assortment of bulbs, corms, rhizomes, tubers, and tuberous roots. Yet like buried treasures, summer-flowering bulbs and bulblike plants yield rewards to gardeners willing to give them the extra care they need to flourish from one year to the next.

The rewards include a striking array of flower colors and forms, and often rich fragrances and handsome foliage. The extra care many of these plants require comes after their bloom season. While baby gladiolus corms and lily bulbs can stay in the ground year-round, most of the other plants, including dahlias and tuberous begonias, would succumb to the effects of cold weather, soggy soil, or disease if they were allowed to remain in the garden over the winter. You'll find recommendations for digging and storing these plants in the "Growing tips" that follow. But if you lack the space or the inclination to store bulbs. you can always plant new ones each year. For bulb sources, see page 118.

ACIDANTHERA (Gladiolus callianthus). Corms, all Sunset climate zones. Blooms spring or summer. Fragrant flowers shaped like stars are creamy white with chocolate brown or maroon markings in the center. Blossoms 2 to 3 inches wide and 4 to 5 inches long open 2 to 10 at a time on 2- to 3-foot-tall stems over swordlike leaves. The variety 'Murielae' grows taller and has crimson-blotched blooms.

Growing tips. Full sun. Planting times are the same as for garden gladiolus (at right). Set corms 3 to 4 inches deep and 6 inches apart. After bloom is finished and leaves turn yellow, dig corms and prepare them for storage as you would garden glads. In the mildest California climates, they can remain in the ground during the winter.

CALLA (Zantedeschia). Rhizomes, zones 5, 6, 8, 9, 14-24. Blooms spring or summer, depending on variety. Resembling fluted cups, flower bracts (called spathes) - pure white, cream, gold, yellow, pink, or spotted - surround a central yellow flower spike (spadix). Arrow-or lance-shaped leaves are glossy green or spotted white. Common calla reaches 2 to 4 feet tall; dwarf pinks, yellows, and oranges grow to half that size.

Growing tips. Full sun near the coast, partial shade inland. In well-drained soil, set rhizomes 4 to 6 inches deep and 1 to 2 feet apart. Keep soil moist. In mild-winter climates, common white calla can stay in the ground with good drainage. The dwarf varieties need to be dug up. In gardens that get heavy frost or have poor drainage, dig the rhizomes in late summer and store at 40 [degrees] to 50 [degrees] in peat moss or sawdust.

DAHLIA. Tuberous roots, all zones. Blooms summer through fall. No other summer bloomer can surpass the dahlia's variety of floral forms - from frilly anemone to spiky cactus types - in a spectrum of warm colors. Some dahlias bear blossoms as large as dinner plates, but the best kinds for bouquets have flowers 5 to 6 inches across with long, sturdy stems. Plants range from 15 inches to 6 feet tall; stake varieties that grow more than 4 feet tall.

Growing tips. Full sun near the coast, light shade in hottest areas. Plant after last frost in warm soil tilled about a foot deep and blended with ground bark or another organic amendment. Set tubers 4 to 6 inches deep; space tall varieties 2 to 3 feet apart, small ones 1 to 1 1/2 feet. Feed plants monthly with a dilute low-nitrogen fertilizer. Avoid wetting foliage, to discourage powdery mildew. In fall after bloom is finished and foliage dries, cut plants back to 4 inches above the ground. No more than one week later, dig the tubers, place them in newspaper-lined boxes with lightly moistened sawdust or vermiculite, and store at 45 [degrees].

GLADIOLUS. Corms, all zones. Blooms spring or summer. Garden gladiolus bear gaudy flower spikes up to 5 feet tall that burst with as many as 12 to 14 blossoms. Flowers come in a wide range of colors from white to green. Miniature glads have 3-foot-tall spikes with 15 to 20 flowers. Hybrids of baby gladiolus (G. colvillei) grow 11/2 feet tall and bear white, pink, red, or lilac blooms in solid shades or blotched with contrasting colors; their corms can be left in the ground to naturalize.

Growing tips. Full sun. Planting times vary by region: January through March along most of the California coast; November through February in the Southwest's low and intermediate deserts; April through June in the Pacific Northwest; May and June in the coldest climates. Before planting, treat corms of garden glads with bulb dust (insecticide-fungicide). Set corms about 4 inches deeper than their height; space big corms 6 inches apart, smaller ones 4 inches apart. Keep soil evenly moist. When young glads develop five leaves, apply a complete fertilizer 6 inches from the bases of plants. Control thrips if necessary by spraying insecticidal soap. After bloom is finished and leaves turn yellow, dig corms and cut off tops. Dry corms for about three weeks, then pull off and discard the old corms and roots. Save the new corms, dust them with diazinon, and store in flats or trays in a cool (40 [degrees] to 50 [degrees]), dry place.