Introduction

Tuberous begonias grow in partial shade but usually not as well in deep shade or full sun. Provide a well-drained soil. The plants need frequent watering and fertilization but excess of either causes flower bud drop. The plants are quite brittle, and staking helps them tolerate violent weather. The single female flowers are removed before seed forms to keep the plant blooming. The females are on either side of the double male flowers.

General Information

Scientific name: Begonia tuberhybrida

Pronunciation: bee-GO-nee-uh too-bur-HYE-brid-uh

Common name(s): Hybrid tuberous begonia

Family: Begoniaceae

Plant type: herbaceous; bulb/tuber; annual; perennial

USDA hardiness zones: all zones (Figure 3)

Planting month for zone 7: May

Planting month for zone 8: Apr; May

Planting month for zone 9: Mar

Planting month for zone 10 and 11: Oct; Nov; Dec

Origin: not native to North America

Invasive potential: not known to be invasive

Uses: edging; hanging basket

Availability: somewhat available, may have to go out of the region to find the plant

Description

Height: .5 to 1.5 feet

Spread: .5 to 1.5 feet

Plant habit: round

Plant density: moderate

Growth rate: moderate

Texture: medium

Foliage

Leaf arrangement: alternate

Leaf type: simple

Leaf margin: lobed

Leaf shape: cordate

Leaf venation: pinnate

Leaf type and persistence: not applicable

Leaf blade length: 2 to 4 inches

Leaf color: green

Fall color: not applicable

Fall characteristic: not applicable

Flower

Flower color: white; pink; salmon; orange; yellow

Flower characteristic: showy

Fruit

Fruit shape: no fruit

Fruit length: no fruit

Fruit cover: no fruit

Fruit color: not applicable

Fruit characteristic: inconspicuous and not showy

Trunk and Branches

Trunk/bark/branches: not applicable

Current year stem/twig color: green

Current year stem/twig thickness: thick

Culture

Light requirement: plant grows in the shade

Soil tolerances: sand; acidic; loam; clay

Drought tolerance:

Soil salt tolerances: unknown

Plant spacing: 6 to 12 inches

Other

Roots: not applicable

Winter interest: not applicable

Outstanding plant: not particularly outstanding

Pest resistance: long-term health usually not affected by pests

Use and Management

Tubers are started in February or March at temperatures of 65°F to 68°F. Start tubers, indented side up, on a layer of peat. When new growth is three to four inches tall, repot and cover the tuber. In central and south Florida, the tubers are planted in fall for use as a cool season bedding plant.

Following a reduction in blooming and yellowing leaves, the leaves and stems fall off the bulb. The tubers are dug when the leaves and stems fall off. Do not break off the stems but wait until they fall off naturally. Injured bulbs should be exposed to air to allow the area to dry. Wash tubers and allow them to dry before storing. Dried tubers are covered with peat or sand and stored at 45°F to 60°F.

Propagation is by stem cuttings or by tuber division. Stem cuttings are made from surplus shoots which arise from the tuber. Stem tips may also be used. The cuttings are three inches long and are cut off just below a node. Sand may be used as the rooting media. Keep cuttings out of direct sun and in temperatures between 60°F and 65°F. Rooting occurs in five weeks. Tuber division is the other way to propagate the plants. Divide the tuber so each division has a bud and use a fungicide to prevent rot. Allow the pieces to dry several days then place them one-half inch deep in sand. The new plants develop more rapidly with bottom heat. Pinch off the first flower buds.

Thrips cause irregular reddish -brown lines on the upper sides of the leaves. Spots form on the undersides of the leaves, especially along the main veins. The leaves may be deformed.

Black vine weevil grub eats the roots causing wilting and death.

Mites stunt the new growth.

Pests and Diseases

Begonias will be attacked by powdery mildew, especially if growing in the shade.

Leaf spots may be found on tuberous begonia.

Stem rot causes the stalks to rot and collapse. The rotted areas are usually black. Avoid crowding and remove any infected plants.