It’s time to bring on the begonias
By Dawn Pettinelli - UConn Home & Garden Education Center
Feature Article - posted Fri., Jan. 28, 2011
Begonias are among the most widely-grown and diversified group of houseplants. There are around 1,500 species of begonias found throughout the world’s tropical and subtropical regions. The ones sold as houseplants started out as understory plants in their native habitats. Much hybridization has occurred. Some begonias are valued for their showy blossoms, while others are highly prized for their decorative foliage. Not only do begonias make excellent houseplants, but some species can be used as summer bedding plants and in outdoor planters or hanging baskets.
Begonias are not difficult to grow, if you keep in mind where they come from. All begonias perform best in bright, indirect light, although a few will tolerate full sun. Varieties grown for their foliage often have slightly lower light requirements. The intensity of light, however, will affect their foliage color. The brighter the light, the more vibrant their foliage. They prefer relatively high humidity, which can sometimes be hard to provide them with when the furnace or wood stove is blowing out hot, dry air during the cold winter months. Try moving them to a more humid area – like the bathroom or kitchen – grouping them together, or setting them on pebble trays filled with water.
A potting mix for begonias should contain a fair amount of organic matter, and most soil-less mixes fit the bill. Begonias should be kept moderately moist. They can tolerate an occasional drying out, as you might expect if you feel their waxy or succulent leaves, but they abhor wet feet. Never let them sit in a saucer full of water. Adequate drainage is essential. They do best situated where temperatures do not go below 60 degrees F.
Begonias are primarily divided into three main classes, although now quite a few interclass hybrids exist. All have both male and female flowers occurring separately on the same plant. The evergreen flowering type begonias include the most commonly grown bedding plant, the wax begonia. Wax begonias have glossy foliage in bright green, red-tipped green, maroon and bronze. Flowers come in pink, red and white, and may be single or double. The seed is very fine, almost dust-like, and this plant is often easier to root by cuttings than seed. Simply insert them into a moistened sand and perlite mix. Double-flowered varieties are sterile and must be vegetatively propagated.
This group also includes the cane-stemmed variety, which produces tall, bamboo-like stems but is exceptionally easy to grow. The ‘Angel Wing’ and ‘Devil Wing’ begonias fall here. Most cultivars benefit from regular prunings. The shrimp begonia is a great candidate for indoor, winter-flowering, hanging baskets.
Tuberous begonias, as the name implies, are generally grown from tubers, although seed has been recently made available for some cultivars. I highly recommend pelleted seed for anyone wanting to try it. These begonias are renowned for their beautiful, large blossoms in shades of pink, orange, scarlet, yellow, salmon and white. The shapes of the blossoms also vary quite widely. Tubers are planted hollow side up with the top slightly above soil level.
Here in New England, if planted in mid-March, tuberous begonias will be ready to set out by Memorial Day, should begin bloom by the end of June, and will continue through first frost.
The third group of begonias is rhizomatous-rooted. These species and cultivars form a thick stem used for water storage during dry seasons in their native habitats. Perhaps the most popular of the rhizomatous rooted class are the Rex begonias, grown for their spectacular foliage. Leaves have a metallic sheen and come in colors such as pink, bronze, maroon, brown, black and red.
If you want information about how to grow begonias or on any other gardening or home topic, call, toll-free, 877-486-6271, visit the website www.ladybug.uconn.edu, or contact your local Cooperative Extension Center.