Rex Begonias

Rex begonias are a great plant to brighten up the winter.  As a houseplant their colorful foliage will add zest to the windowsill.  And they can be moved outside in summer to bring color to shady containers and baskets.

Rex begonias have large leaves, generally pointed, although rounded and other shaped leaves are not uncommon.  The leaves are thick and wrinkled looking and come in a variety of stunning colors and patterns.  Some plants can reach a foot high and some plants have been bred that stay quite small.

Rex begonia are great collectors plants because there are hundreds of varieties for sale.  You’ll have a hard time picking just one plant to grow.

Growing conditions

Rex begonias are relatively easy to grow except for one requirement.  They need humid conditions to keep leaves from getting crispy edges and eventually falling off.  If you have a well lit bathroom Rex begonias may thrive there.  They may also do well over the kitchen sink. 

If you don’t use a humidifier in the house in the winter you can place the rex begonia in a shallow tray of water with stones or marbles in the bottom to keep the pot bottom above the water line.  Grouping Rex begonias with other plants also helps with humidity.  Misting the plants doesn’t work well as Rex begonias will get spots on the leaves from water sitting on them.

Rex begonias like bright light but not direct sunlight.  An east or north windowsill will generally work or place them about a foot away from a south or west window. Good, strong light brings out the best leaf color.  In the summer outside they need shade.  Rex begonias can also be grown under artificial light.

Plant the Rex begonia in good, light potting soil or use an African violet soil.  Keep the soil moist but don’t let the pot get waterlogged.   While Rex begonias like moisture and humidity their roots also need some air.

Fertilize lightly beginning in March in Michigan through September, maybe once a month. Don’t over fertilize, as foliage plants, Rex begonias don’t need much fertilizer.   Keep dead leaves picked off.  Plants may go through a period of adjustment when moved, especially from a humid greenhouse or from outdoors into a drier indoor location.  Some plants will even go dormant.

If the Rex begonia does seem to drop all its leaves and die down to soil level all may not be lost.  Put the pot in a clear plastic bag and set it out of direct light for a few weeks.  Check from time to time to see how moist the soil is and add a little water if it is very dry.  After a month or so- or sooner if you notice new growth, take the plant out into bright light and resume watering.

Like most begonias, Rex begonias flower.  However this species of begonia does not have very showy flowers and you will probably want to clip out the flower stems that peek out from the center so the plant concentrates on producing its showy leaves.

Rex Begonia propagation

Rex begonias are one of the few plants that propagate readily through the leaves.  You can remove a young leaf and stem and insert the stem into a moist pot of planting medium.  Place the pot in a clear plastic bag in bright indirect light and keep moist.  Wait for a new plant to form at the leaf base. Or you can get many plants from one leaf using this method.

Find a wide container that a large leaf can lay flat on.  Flip a Rex begonia leaf over and make small cuts across several of the large veins.  Don’t cut all the way through the leaf.  With a cotton swab rub some rooting powder- found in houseplant supplies- on each cut. 

Fill the container with moist potting medium.  Place the leaf on it cut side down and weigh down the leaf with small pebbles, metal nuts or some other small item so that the cut vein contacts the soil.  Place in a clear plastic bag in bright indirect light and wait for new plants to form at the leaf surface by each cut.

These wonderful plants are a great way to share plants between several plant lovers.  Each gardener can buy a different variety and start new plants to trade with other gardeners.   Even if you keep all of your plant babies you’ll enjoy the color the Rex begonia brings to dull plant collections.