Begonia rex-cultorum

Rex begonias need regular water, but be careful not to overdo it. They grow when there is moisture but be careful when they move the leaves so that they do not stay too wet and promote carbon dioxide. Allow the soil to dry until touched before watering. Do not allow the soil to dry out, or the plant will start to wither. The soil should be watered to make it feel soft but evenly moist.

Rex begonias perform best at moderate temperatures (60 to 70 degrees Fahrenheit) and moderate humidity (approximately 50 percent). Growth will be slower at freezing temperatures, and some species of begonias fall into a state of insomnia during the winter due to lack of light.3 Like other begonias, rex, and other begonias leaves prefer the same moist, soft spot where understory ferns thrive.

This plant will thrive in moderate humidity, which is probably the level in your home. However, misting it a few times a week can be very beneficial. Make sure the room has good ventilation.

Apply liquid fertilizer weekly with quarterly or partial strength every two weeks.

Rex begonias need a little pruning unless the long, bare stem needs to be pruned or you would like to build a full plant. To use clean pruning pieces, simply cut the stem back to the base, and the remaining part should sprout new leaves and stems. Biting tips on small plants help them grow full.

Rex begonias are generally non-fatal but are still considered toxic plants for both people and pets. Ingesting begonias can elicit toxicity symptoms, such as a burning sensation in the mouth, throat, lips, and tongue with swelling and difficulty speaking. You might also experience vomiting and nausea.