Begonia Flower Basics
There are several types of begonia popular among gardeners for their variety of flower colors, shade tolerance, and the fact that they flower all throughout the summer. Wax begonias and tuberous begonias are among the most common types.
Wax begonias do well in sunnier areas, and are preferred by southern gardeners for their drought and heat tolerance.
Tuberous begonias prefer shade, and don’t do as well in heat and humidity. Begonias can range between 8 inches and two feet tall. They grow well as bedding plants, in pots, hanging baskets, and in window boxes, but look especially attractive when planted in large masses. They grow well in partial shade, but need some sun for blooming well. They also prefer a moist, rich, well-drained soil.
Wait to plant until soil and air temperatures are in the 60s, as cold planting will adversely affect begonias’ growth. Plant begonias up to a foot apart, as this will allow them to leaf out and bloom to their full potential. Smaller plants can be placed closer together; wax begonias, for instance, will be fine about 6 to 8 inches apart.
Set seedlings or cuttings out to root in the spring, after any frost danger is past. If you are planting tuberous begonias, these are propagated with tubers, therefore their name. They must be dug up in the fall, since they won’t last the winter outdoors.
Store tubers indoors through the winter; they will sprout shoots in the spring and can then be tended as seedlings until they are big enough to transplant outdoors. Do this after frost danger has passed. Check your specific variety of begonia to be sure of its sun or shade requirements, as they do vary even within species and cultivars, and plant it in an appropriate location.
Caring for Begonias
Begonias do not need a lot of fertilization. Fertilize with a balanced 10-10-10 fertilizer once in the early spring to encourage new growth and good blooming, but refrain from fertilizing the rest of the growth cycle. Begonias are popular for the minimal are they need. In shady areas, they’ll need less water, as the sun won’t evaporate as much of their water as in full sun placements. Water when the soil at the base of the plants dries out to the touch; keep it moist, but not wet. Overly wet soil can encourage mildews and rots.
Begonia Pests and Diseases
Several pests and diseases affect begonias. Among fungal disease possibilities, gray mold and powdery mildew are the most common. These can be avoided by making sure mulch is not too deep, and not over watering the plants. Stem and root rot can also happen when soil is too wet, or if you water improperly, splashing water onto leaves and stems rather than directing it into the soil.
Prevent leaf spot and blight by pinching off faded or wilting blooms and dried up, curled leaves. Keep an eye out for dead, dying or diseased parts of plants, and remove and discard them quickly so as not to give insects and diseases an opening into the plant.
As far as common insects, slugs and snails are often attracted to begonias, as are mealy bugs and spider mites. Prevent mealy bugs by keeping the area well weeded, and avoiding high-nitrogen fertilizers. If you get spider mites, wash the plants thoroughly with a dilute soap mixture, to get rid of the eggs and larvae. Handling the problem while the infestation is small is best, as they can spread to other plants quickly after hatching.
Want to learn more about growing begonias?
Check out these sites for more information:
Clemson University in South Carolina has a guide to many types of begonias.
The American Begonia Society provides articles and a virtual greenhouse exploring begonias.
Wax begonias are explained by the University of Illinois Extension.