Rex begonias are grown specifically for their attractive foliage, and are almost exclusively indoor container plants. They require a bit more care than your average houseplant, but the variegated, colorful leaves add a bit of life to any indoor environment. The leaves of the rex begonia plant may be smooth or bumpy, come in numerous shapes, and are streaked with colors such as white, yellow, pink or purple. There are numerous varieties of rex begonias available, but care and maintenance is the same for all types.
Plant rex begonias in a container or hanging basket with drainage holes in the bottom. Use a commercial peat-lite potting mix, and always avoid heavy and poor-draining soil mixes. Place the container in an area of the house which receives low to medium bright, indirect sunlight and stays at a constant temperature between 65 and 75 degrees Fahrenheit.
Keep the humidity around rex begonia plants at around 50 percent at all times. This is important to keep the foliage growing healthy, although it is sometimes difficult to achieve indoors. Place a humidifier near the plant, or place the plant on a shallow tray filled with water and pebbles to increase humidity.
Water rex begonias when the soil just begins to dry out, usually about once per week. They like moist soil, but it cannot be too wet or fungal diseases could occur. If you have a variety of rex begonia that goes dormant in winter, water sparingly until spring when new growth begins.
Feed rex begonias once every two weeks during spring and summer using a balanced liquid houseplant fertilizer. Reduce feeding to once per month during winter. Refer to the manufacturer's instructions for proper dosage and application. Water just after applying to distribute nutrients and prevent root burn.
Prune rex begonia foliage only if necessary to remove dying, diseased or dead leaves. Other than this basic maintenance, they require no other pruning or cutting. If flowering occurs, which happens only occasionally indoors, remove blooms after they have faded.