Care and Feeding of Begonias

Planting Site

• Neither perennial or annual begonias tolerate frost, so plan to plant them outdoors after spring frost danger is past. Tuberous, rex and hardy varieties prefer sites with full to partial shade. Dragon wing varieties tolerate sun or light shade, but wax varieties flower best in full sun. Plant all begonia varieties in rich, well-drained soils that retain some moisture without becoming soggy. Plant begonias in the garden bed at they same depth they were growing at in their nursery pots, with the exception of tuberous begonias. Plant the tubers so their tops sit no more than 1 inch beneath the soil surface, as deeper planting can result in rot.

Watering

• Shade-grown begonias experience less soil drying than those grown in full sun. All begonias require soil that remains evenly moist but doesn't become soggy. Tuberous begonias are particularly sensitive to soggy soil and suffer root rot in wet soil. Once-weekly watering that provides about an inch of moisture is usually sufficient. Keep the top 6 to 8 inches of soil moist, watering more or less frequently as necessary. A light mulch covering helps retain soil moisture, but don't cover the base of the plant in the mulching material.

Fertilizer

• Light fertilization helps encourage continued healthy growth and flower bud formation. Avoid over fertilizing, as begonias are light feeders and receive the majority of their nutrients from those already present in the soil. Amending the planting site with compost before setting out the begonias provides for most nutrient needs. A light fertilization with a soluble flowering plant food every two weeks, diluted to half the recommended dosage, provides any other nutrients the begonias need.

Winterization

• Perennial begonias require some preparation to survive winter. The hardy begonia varieties typically die back to the ground after frost but the roots survive winter. Mulching over the plants after they die back, then removing the mulch as temperatures warm in spring, usually allows the plant to survive in the garden. Tuberous begonias won't survive prolonged frost. Dig up the tubers as soon as the frost kills back the leaves. Dry the tubers indoors for three weeks then store them in dry peat moss in a 40 to 50 F location until replanting in spring or early summer.