Begonia

Fundamental Facts

HARDINESS: Tender
PREFERRED SOIL pH: Near neutral
PREFERRED SOIL TYPE: Well-drained, fertile
PREFERRED LIGHT: Sun to partial shade
ATTRIBUTES: Season-long flowers, neat plants; use for beds, baskets, and containers
SEASON OF INTEREST: Summer to fall
FAVORITES: Wax begonia 'Wings', 'Cocktail', and double 'Queen'; tuberous Nonstop hybrids, and Giant Cascade Doubles
QUIRKS: Wet leaves turn dry and brown in strong sun
GOOD NEIGHBORS: Impatiens, petunias, Shasta daisies, scobiosa
WHERE IT GROWS BEST: Partial shade with crumbly, fertile soil
POTENTIAL PROBLEMS: Powdery mildew, sunburn
SOURCE: Cuttings, seeds, tubers
DIMENSIONS: Wax 8-14 in (20.3-35.6 cm) tall and wide; tuberous 1 ft (0.3m) tall, 1 to 3 ft (0.3 to 1 m) wide

Begonia in the Landscape

The beauty of begonias lies in their versatility. At 1 ft (0.3 m) high or under, sun-loving, mound-shaped wax begonias are veterans of containers and favorites for edging shrub beds or mixing with other small annuals. These fibrous-rooted plants tolerate shade, drought, and humidity and spend the entire season smothered in a wealth of handsome little open-faced flowers. The waxy, rounded leaves are either deep emerald green or luscious bronze, but they are always half buried beneath snow white, pink, rose, or red blossoms with contrasting yellow centers.

Improving on Perfection

There are many wax begonias sold in spring. If you prefer green leaves, look for the Wings mix with a range of flower colors and wide, open-faced single flowers. For bronze foliage, try the dwarf Cocktail series, which remains 7-8 in (17.8-20.3 cm) tall and includes rosy-flowered 'Gin', deep scarlet 'Vodka', and pearly white 'Whiskey'. For many-petaled flowers, look for 'Queen', which is also available in a range of colors.

Growing Wax Begonias

Whatever you select, wax begonias appreciate fluffy soil enriched with compost or leaf mold, and they will flower continuously when fertilized throughout the growing season with a balanced formula, such as 20-20-20, applied every 3 weeks. Water when the soil dries and trim plants as needed to keep them neatly shaped. Of all begonias, wax begonias are the least susceptible to diseases and insects. If ragged holes appear in leaves, slugs are the likely culprits. Control these mollusks by putting out commercial traps or shallow saucers of beer, which lure and drown slugs.

You can easily increase your stock of wax begonias by rooting 3 in (7.6 cm) long stem cuttings in a pot of moist potting soil. To keep your favorite plants from freezing, dig them up in fall, pot, and overwinter indoors on a sunny windowsill.

Tuberous Begonia for Outdoors

While wax begonias are the queens of the bedding scene, the shade-loving tuberous begonias, with their large, roselike blossoms and deep green maple-shaped leaves, are head-turning accent plants for beds and containers. They come in many sizes and growth habits.The 12 in (30.5 cm) wide Nonstop hybrids produce masses of double and semidouble 2-3 in (5.1-7.6 cm) diameter blossoms in yellow, orange, red, burgundy, and pink virtually all summer. For breathtaking container plants, look for varieties with double blossoms in a solid color, or with petals edged in another color, such as 'Pacific Giant'. Giant Cascade Doubles yield a shower of 5 in (12.7 cm) wide blossoms in red, white, orange, pink, or yellow.

As their name reveals, tuberous begonias sprout from tubers, and you can either buy potted plants or start your own from tubers. Start tubers indoors in early spring, setting them just below the surface of moist, fertile, peat-moss-enriched soil. Set the pots in a sunny window and move them outdoors when the weather is warm. Always keep tuberous begonias in partial shade and water them as soon as the soil is dry. Discourage disease by removing shriveled leaves and blossoms. Keep the foliage dry when watering to avoid sunburn and powdery mildew, a fungal disease that disfigures leaves with white or gray powdery splotches. Remove and dispose of infected leaves and move infected plants to a dry, airy location.

To overwinter tubers, allow the soil in the pots to dry in fall, then remove and store the dormant tubers in paper bags filled with dry peat moss, in a cool, dark place, such as a basement, until time to start the tubers the following spring.