Starting New Begonia Plants from a Leaf
Expand your houseplant collection with leaf cuttings of Rex, angel wing and other large leafed begonias.
Fill a container with a moist well-drained potting mix. It should be wide enough to accommodate a flattened leaf. Remove a healthy leaf and place it so the underside of the leaf is lying flat on the potting mix surface. Use a sharp knife to slice through several large veins. Anchor the leaf against the soil surface with hairpins or small stones.
Set it in a bright location out of direct sunlight. Loosely cover with an open plastic bag to increase the humidity. Water the soil thoroughly with tepid water and often enough to keep the soil moist.
New plants will eventually form where the veins were sliced and often by the leaf stem. Once the plantlets develop several true leaves, you can carefully dig, divide and replant them into their own containers.
A bit more information: You can also propagate these begonias with a leaf-petiole cutting. Remove the leaf from the plant, leaving the leaf stem (petiole) intact. Bury just the petiole in the potting mix. Leave the flattened portion of the leaf (blade) attached and above the soil surface. Roots and a new plant will start to grow in a month or two.