Bright flowers of tuberous begonias (Begonia tuberhybrida) close up in a garden. (Photo: Shutterstock)

Carol O'Meara, Colorado State University Extension

Carol O’Meara, Colorado State University Extension

LONGMONT – Every so often a new plant catches my eye, stopping me in my tracks at garden centers with their beauty. In truth, it happens more than I admit; like the dog distracted by squirrels, there are days when I can’t get down an aisle in a greenhouse without dashing back and forth. These days, the plants clamoring for my attention are begonias.

Breeding has brought us glorious selections in this shade loving plant, and if you’ve been thinking they’re the ho-hum houseplant for a dimly lit room, you’re missing out on a showy display of leaves and flowers that brighten landscapes and interiors. Here’s a quick rundown on the types to choose from:

Most commonly grown wax begonias (Begonia semperflorens) have waxy leaves and flower continuously. Leaves vary in color from green to bronze or red, and flowers may be single or double in red, pink, orange, or white. These prefer moderate to bright light in winter and partial shade in summer.

Cane, or “angel wing,” begonias have bamboo-like stems with leaves shaped like wings. Superba canes are large, often soaring to 12 feet tall. Dwarf types are available. True “angel wing” begonias are slightly different than superba; these sport the pointed leaves that gives this type their name. Both types are exuberant bloomers, with flowers produced in large, pendulous clusters.

Rhizomatous begonias have decorative leaves as well as a showy display of spring flowers. Its heavy, succulent stem grows just above the soil surface and sends out adventitious roots. Leaves come in various earth tones with smooth or hairy surfaces; some are deeply lobed, while others are round. Rex begonias are part of this group. Keep them in filtered or indirect light.

Tuberous-rooted begonias are popular for their flowers more than leaves; the blooms can be a demure half-inch to more showy, rose-size flowers. Don’t be alarmed if they go dormant – tuberous begonias need rest during fall and winter.

Grow begonias in moderate to cool temperatures. Plant in media rich in organic matter, such as peat or compost, mixed with sand, perlite, or vermiculite. Begonias should be kept moist, but allow them to dry slightly between watering. Humidity is crucial to good begonia health, so keep the pot on a pebble tray with water.

Begonias thrive in medium light but will tolerate low light, making them ideal pick-me-ups for offices. With the exception of wax begonias, keep them from bright light, which damages many.

Fertilize regularly with a fertilizer higher in nitrogen than phosphorus and potassium. But begonias are sensitive to salts, so follow package instructions to avoid over fertilization. Begonias aren’t fussy, with few pests; mealy bugs – small, white, waxy coated insects that gather at leaf junctions – are most often the insects on begonias. Trim yellowing, dead leaves from the plant.

By Carol O’Meara, Colorado State University Extension. Colorado State University Extension, together with Boulder County Parks and Open Space, provides unbiased, research-based information about consumer and family issues, horticulture, natural resources, agriculture and 4-H youth development. For more information contact Colorado State University Extension at the Boulder County Fairgrounds,
9595 Nelson Rd., Box B, Longmont, 303.678.6238, e-mail [email protected] or visit