How to Care Begonia Plant:
Tuberous begonias will naturally die back each year. Start decreasing water in late summer to early fall and trim back foliage when it starts to yellow. Dig up the tubers at the first threat of frost. Clean any remaining dirt from the tubers and dry them on newspaper in a sunny location for about a week. To prevent powdery mildew, lightly dust them with sulfur powder and store individually in paper bags or wrapped in newspaper.
Rhizomatous and wax types don’t die back and are usually pinched or lightly pruned each year to keep them healthy and encourage full, but compact growth. In warmer climates, this is best done in spring. In cooler climates, you can do this in fall as a clean-up before bringing them inside for the winter. In addition to cutting them back, check for signs of pests or disease before moving them indoors. Slowly acclimate them to their new inside location by first placing in a bright window and gradually decreasing the amount of light. This will to help prevent stress, which causes the leaves to drop. Once warmer temperatures return, reverse the process and move them back outside. See below for information on growing as houseplants.
For all types, deadheading spent begonia flowers keeps plants clean and healthy, as well as promotes more blooms.
All begonias like evenly moist, well-draining soil with some added organic matter.
Amendments and fertilizer:
For general growing purposes, apply a balanced water-soluble fertilizer once a month in the growing season. For plants grown strictly for their foliage, like angel wings, use a fertilizer that is higher in nitrogen.
Regular watering is important for healthy plants. The soil should remain moist at all times, but not too wet, as this can cause rot. Water at the base of the plant to keep the foliage dry and prevent leaf spot and fungal diseases.
Diseases and pests:
Susceptible to powdery mildew, mealy bugs, mites, thrips, and whitefly. Stem rot and rhizome rot can be caused by overwatering and soggy soil.