Rex Begonia (Begonia spp.) - How to Grow & Care Guide

Plant Snapshot

Common Name: Rex Begonia
Latin Name: Begonia spp.
Hardiness Zones: USDA 10–11 outdoors. Treated as a houseplant or annual in colder zones.
Typical Height: 6–12 in (15–30 cm) tall depending on cultivar.
Typical Spread: 8–12 in (20–30 cm) wide for many cultivars.
Bloom Period: Occasional small flowers, usually spring to summer in favorable conditions. Grown mainly for foliage.
Soil Preferences: Rich loose potting mix high in organic matter that drains well. Slightly acidic to neutral pH around 5.5–6.5. Waterlogged soil leads to root rot and crown rot.
Light Preferences: Bright indirect light or filtered shade. Avoid direct hot sun which can scorch leaves. Tolerates lower light with reduced leaf contrast.
Toxicity: Reported toxic to pets if ingested causing oral irritation, drooling, and vomiting. Handle with care if you have sensitive skin.
Propagation: Leaf cuttings, rhizome division, stem cuttings and seed. Leaf cuttings are commonly used for Rex cultivars.

Key Facts

Grown primarily for dramatic, colorful foliage.
Includes numerous cultivars in the Begonia rex-cultorum group.
Tender perennial in warm climates and a common houseplant elsewhere.
Prefers bright indirect light and higher humidity.
Likes a rich loose potting mix that drains well.
Produces small, inconspicuous flowers but is valued for leaves.
Easily propagated by leaf cuttings or division.

Rex Begonia is a group of cultivars grown for dramatic, colorful foliage and used mainly as an indoor accent or shaded patio plant. They reward bright indirect light and higher humidity while remaining tender outdoors in warm climates.

Identification

Rex Begonia are prized for bold patterned leaves rather than flowers and include many cultivars in the Begonia rex-cultorum group. Plants are generally compact, typically 6 to 12 inches tall with a spread often 8 to 12 inches, and they produce small inconspicuous flowers in favorable conditions.

Where to grow and best uses

Grow Rex as a houseplant, terrarium specimen, or shaded container on a protected porch. Outdoors they perform well only in warm USDA 10 to 11 zones and should be treated as an annual or brought inside in cooler regions. Use them for tabletop displays or mixed shade pots where foliage is the main show.

Light and humidity

Place Rex in bright indirect light or filtered shade to preserve leaf color and patterning. Avoid direct hot sun which can scorch leaves. Higher humidity improves leaf contrast so group with other plants or use a pebble tray or humidifier when indoor air is dry.

Soil and potting

Use a rich loose potting mix high in organic matter and good drainage with a pH around 5.5 to 6.5. Avoid heavy, waterlogged soils which lead to root rot and crown rot. An airy mix with peat or compost and added perlite gives the best balance of moisture retention and drainage for containers.

Watering

Keep the soil evenly moist but never waterlogged to prevent root and crown rot. Allow the topsoil to dry slightly between waterings so roots do not sit in water. Leaf color and vigor decline when plants are kept too wet or allowed to dry out completely.

Planting time and spacing

Plant or pot Rex when indoor temperatures are stable or after danger of frost has passed outdoors. Space plants roughly 8 to 12 inches apart to allow clump formation and air circulation. In containers choose a pot large enough for the expected 8 to 12 inch spread.

After flowering and seasonal care

Flowers are usually small and not the main feature. Remove spent flower stalks and trim any damaged leaves to keep the plant tidy. Reduce watering during cooler, low light months and move plants indoors before frost in colder climates where they are not hardy.

Propagation

Propagate Rex by leaf cuttings, division, or stem cuttings with leaf cuttings commonly used for many cultivars. Division is useful for larger clumps. Propagation technique varies by cultivar so try the method that matches the plant form you have.

Problems and troubleshooting

The main risks are root and crown rot from poor drainage and leaf scorch from too much direct sun. Low light reduces leaf contrast and patterning. Monitor potting mix moisture and move plants to brighter filtered light and higher humidity when foliage looks dull.

Toxicity and pet safety

Begonia species have been reported by the ASPCA to be toxic to cats and dogs causing oral irritation and vomiting if ingested. Sap can irritate sensitive skin. Keep Rex out of reach of pets and consult regional poison control for definitive guidance in your area.

Frequently asked questions

How fast does Rex grow?: Growth rate varies by cultivar and conditions but is generally moderate. Many cultivars remain compact and typically reach 6 to 12 inches tall while forming clumps about 8 to 12 inches wide.
Are Rex Begonias hardy outdoors?: Rex are tender and only reliably hardy outdoors in USDA 10 to 11. In cooler zones keep them as houseplants or move them indoors before frost.
How do I propagate Rex?: Use leaf cuttings, division or stem cuttings. Leaf cuttings are commonly used for many cultivars and division works well for established clumps.
Why are my Rex leaves losing color?: Leaves lose contrast in low light or under very dry indoor air. Increase bright indirect light and humidity to restore stronger coloration.
Will Rex rebloom?: They produce occasional small flowers in spring to summer under favorable conditions but are grown primarily for their foliage rather than blooms.