Among the various types of begonias, the B. Rex are some of the most beautiful and stunning plants. Sometimes called painted-leaf begonias or fancy-leaf begonias, these plants are known for their showy, sometimes jaw-dropping leaf coloration. They frequently have large leaves (up to 6 inches long) that are brightly colored in various shades of green, red, silver, and even purple. These plants are grown almost exclusively for their foliage—their blooms tend to be small and less showy, so many growers pinch off blooms to maintain breathtaking leaf displays.

Some types of Rex begonias go into dormancy during the winter.

Growing Conditions:
Light: Bright, indirect light year-round. Because they are not aggressive bloomers, they can tolerate less light than other begonias and will thrive under fluorescent lights.
Water: Rex begonias like even water but hate being overwatered, and they thrive on humidity but don't like direct misting, which encourages powdery mildew.
Temperature: Average to warm (and humid). They cannot tolerate freezing, and some types of Rex begonias go into a dormant period during the fall.
Soil: Airy, light, fast-draining soil.
Fertilizer: Use liquid fertilizer weekly at quarter strength or biweekly at half strength.

Propagation:
The vast majority of begonias offered in the trade are hybrids and thus cannot be accurately propagated from seed. Rhizomatous begonias can be easily propagated by rhizome division during repotting, while almost all begonia species will readily sprout from leaf-tip cuttings.

A rooting hormone can help the cuttings sprout. Rex begonias can also be propagated by pinning a leaf down to the bedding mix and making small incisions in the leaf veins, or by inserting a leaf (with a petiole) directly into the soil.

Repotting:
Rex begonias are rhizomatous plants that grow from a shallow and knobby rhizome.

As such, they do best in large, relatively shallow pots where the rhizome has room to spread. As long as there is still growing room in the pot, the begonia should be considered happily potted. When the rhizome begins to butt up against the pot side, however, it's time to repot into a fresh pot with fresh soil. Divide the rhizome at potting time to increase your plant stock. As with all begonias, don't soak the soil of newly potted plants, but do keep it lightly moist and warm.

Varieties:
Begonia rex is the basis for many hundreds of hybrids, and its forms are too numerous to count. The resulting hybrids are often known in the trade only by fancy trade names dreamed up by growers looking to market their plants. As a result, you might find the same crosses named two different things in different garden centers! One interesting and beautiful begonia that's often included with the Rex begonias as a foliage begonia is the B. masoniana or iron cross begonia. This beautiful plant was introduced to cultivation in 1952 and has puckered leaves with a dark cross in the middle. It's available in various colors.

Grower's Tips:
Because these are primarily foliage plants, careful cultivation is a must to realize their full beauty.

As with other begonias, the Rex and foliage begonias enjoy the same humid, gentle environment of understory ferns. Be especially careful of directly spraying the leaves, as standing water will encourage powdery mildew, which is a disaster on a plant meant to be viewed. Even the best Rex specimen can only be expected to thrive for a few years, but because they propagate so easily, it's a simple matter to keep a steady supply of healthy plants by taking new ones every year.

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LIGHT
A Begonia Rex plant needs plenty of bright indirect light but no direct sun. Since a Begonia Rex does not bloom very often, it does well in less light than some other begonias. Begonia Rex plants can even grow under fluorescent lights.

WATER
Allow the top 50% of the soil to dry out before you water a Begonia Rex. These plants like to be evenly watered but hate being over-watered. During the winter, when a Begonia Rex is dormant, reduce your water.

FERTILIZER
Fertilize in the spring when new growth starts to appear. Feed a Begonia Rex with a balanced plant food every two weeks at ¼ the recommended strength. Feed less in the fall and and not at all in the winter.

TEMPERATURE
Begonia Rex plants like average to warm temperatures and are sensitive to temperatures below 60 degrees. The leaves can be damaged by temperature changes.

HUMIDITY
Begonia Rex plant requires high humidity to grow well, but do not mist to increase the humidity; misting often causes powdery mildew. Cluster your houseplants to create a mini greenhouse effect or put a Begonia Rex on a wet pebble tray to increase the humidity around the plant. Be sure the plant is sitting on the pebbles and not in the water.

FLOWERING
The flowers of a Begonia Rex are very small and inconsequential, and pale in comparison to its gorgeous leaves.

PESTS
The plant pest mealybug can infest sections of a Begonia plant where the leaf joins the stem or the stem joins the rhizome.

DISEASES
Because Begonia Rex plants like high humidity, they are especially prone to bacterial and fungal infections. Never spray the leaves because misting a begoni plant often causes powdery mildew, a disease that destroys the beautiful leaves.

SOIL
Use a loose well aerated soil.

POT SIZE
Begonia Rex plants like large, relatively shallow pots where the rhizomes have room to spread.

PRUNING
Large or gangly Begonias plants can be pruned into shape. Rotating potted Begonias keeps them full and balanced looking.

PROPAGATION
Stem and leaf cuttings are the best ways to propagate a Begonia Rex.

RESTING PERIOD
A Begonia Rex plant rests during the winter months.

POISONOUS PLANT INFO
All Begonias have a #1 toxicity level and are especially poisonous to dogs and cats.