Rex begonias are tropical plants, prized for their colorfully patterned and intriguingly shaped leaves. Although they are at home in a shady garden, they are also popular as houseplants. Many people collect and display several varieties. Most rex begonias sold today are named hybrids, although they are not always labeled.
Common Name:Rex Begonia
USDA Hardiness Zones 10 - 11. Often grown as a houseplant and used in outdoor containers.
ExposureFull sun to partial shade. Avoid direct sunlight. They need some light to keep their coloring, but a bright, indirect light is best.
6 - 12" (h) x 12 - 18"(w)
Bloom PeriodThe flowers tend to be small and incidental, but they will repeat bloom. However the flower stalks are usually removed, to allow the plants energy to be focused on growing leaves.
Begonia rex hybrids have been developed to have unusual markings, leaf shapes and colors. The leaves grow on short leaf stalks, from the underground rhizome. The leaf edges and undersides are covered with short red hairs.
Leaves:Asymmetrical, usually 4 - 9" long and variegated in shades of green, red, pink, purple, silver and brown.
Flowers: The flowers are usually pink, however while a few rex begonias have showy flowers, most are barely noticeable and don't add anything to the appeal of the plant. It’s usually recommended that you cut the flowers and allow the plants energy to go into growing the leaves.
They’re all great and many are unlabled or mis-labeled, so keep your eye out.
Begonia rex ‘Boston Cherries & Chocolate’ Red and Sliver spots on dark leaves.
Begonia rex ‘Escargot’ Spiraling markings and the way the leaves circle inward make each leaf look like a snail.
Begonia rex ‘Fireworks’ Wing-shaped silver leaves are etched with purple
Begonia rex ‘Snow Queen’ - Silvery leaves with good disease resistance.
To really play up the unique qualities of Begonia rex, pair them with solid green plants with different textures or forms.
They look great outdoors in shady tropical gardens. But probably the most popular way to display rex begonias is to collect and group them together, each in its own pot.
Soil: Rex begonias prefer a light, rich soil. When planting directly in the ground, a moist, well-drained location is optimal and mulch will keep the roots shaded. In pots, make sure to provide drainage holes. A peat-based potting mix is ideal for containers.
Water: Begonia rex should be watered when the soil or pot feels dry, but don’t wait until the plant starts to wilt. You can cut back on water during their dormant period in the winter, watering only when the pot dries out.
Humidity is crucial to keeping your rex begonia happy, however spraying the leaves can lead to spotting. It’s better to cluster your plants, so they can create their own humid environment, or use a pebble tray.
Fertilizer: You can feed your potted plants monthly with any good houseplant food. Too much food will make for a scraggly plant, so pay attention and adjust the feeding to suit your variety. Rex begonias can be temperamental and you just have to find the right conditions and balance for your plant. Don’t feed at all during the winter.
Maintenance:Rex Begonias aren't the easiest plants to make happy. They can be very demanding of just the right amount of water, food and humidity. Plants will vary and the only way to know what your plant wants is to watch it, once it has adjusted to its new surrounding. If it's flourishing, continue with what you were doing. If it is droopy or gangly, adjust the light and water. Eventually you'll figure out the right balance.
Repotting rex begonias each spring will ensure that they have plenty of soil to grow in, but they like to be a little bit pot bound. Large or gangly plants can be pruned into shape. Rotating potted rex begonias will keep the plants full and stocky.
Begonia rex is sensitive to temperature changes and to temperatures below about 60 degrees F. (16 C.) You can keep them happy as houseplants or store them dormant over winter, as you would with other tender bulbs.
Pests & Problems:Bacterial leaf spot, mildew and botrytis can occur if the leaves stay wet. Root rot can be a problem in wet areas.
Mealy bugs can also become a problem, especially indoors.