Leaves falling off as daylight hours diminish in the fall indicate that your begonia is becoming dormant. Reduce water as that occurs until all the leaves are gone.

Rex Cultorum Group Begonias are likely to experience dormancy in mid-winter for a period of about two to three months when grown in the New York area. (Not all begonias in this group experience dormancy and some may enter a semi-dormancy.) The plant will drop leaves beginning in the fall and droop as it becomes dormant. Taper off water as this occurs and remove the fallen leaves. If all of the leaves fall, move the plant to a dim location at 60º F. until growth resumes in late winter/ early spring. Keep plants just barely dry at the roots until strong growth is evident. If you are growing these plants under artificial light, they will have a lighter rest and should be kept slightly dryer than usual.

If dormancy initiates in other seasons, check that the temperature and light guidelines are being met and the plant is not being shocked by sudden change.

Read more about caring for your Rex Cultorum Group begonia in our Guide.

Courtesy of NYBG Plant Information Service