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Begonia Toxicity

By Carrie Terry ; Updated September 21, 2017
Begonias need very warm conditions, and often become houseplants in the winter.
begonia image by Maria Brzostowska from Fotolia.com

Begonias are summer-flowering plants closely related to gloxinias. They are descended from tropical plants, and native to rain forests and hot tropical areas, so have a reputation for cold intolerance and difficulty. The flowers grow best in temperatures of 70 to 80 degrees Fahrenheit, which leads many homeowners to grow them indoors. Because begonias are toxic, any homeowner should handle them with some caution.

Begonia Tubers and Rhizomes

Begonias start as tubers, or bulb-like growths, which contain the necessary growing material for the plant. Tubers are hardier than seeds, and are best planted in February, in peat moss or quick-draining soil. These tubers are also the best way to transplant begonias once they've established.

Growing Needs

Begonias are extremely cold sensitive and must stay indoors after the last frost of the season. They require modestly filtered sunlight, and do well in protected areas of the garden, in either pots or under shade trees. According to the Learning Store, begonias only need morning sun to thrive and grow.

Begonia Toxicity

According to North Carolina State University, every member of the family Begoniaceae is mildly toxic. The most toxic pieces of the plant are the rhizomes, tubers and roots.

Effects and Symptoms

North Carolina State University states that begonia toxicity is non-fatal, even if a gardener or pet swallows the plants. Symptoms include burning mouth, throat, lips and tongue, accompanied by some swelling and difficulty speaking. At worst, a person experiences nausea and vomiting.


Begonias poison only those people and animals who physically eat the plants or tubers. Handling the plants is harmless, though gardeners should wash their hands after handling or pruning, to avoid transferring the oil of the begonias to food or face.