Bad girls of the garden get a bum rap

By Lynette L. Walther | Mar 28, 2013
Courtesy of: Longfield Gardens Expect luxuriant growth and fabulous blooms all summer long when you grow tuberous begonias in shaded locations.

Bad girls bad girls, what’cha’ gonna do? With a reputation as belligerent, difficult characters, tuberous begonias are actually more misunderstood than onerous. A little insight goes a long way when it comes to growing these flamboyant flowering tubers, and it doesn’t take much to keep them happy.

For shaded gardens begonias offer irresistible big color blooms that dance non-stop through the summer until frost. Begonias (Begonia × tuberhybrida) are tender summer tubers that produce blooms in a lush palette of colors from the palest pales to vivid-hued showy blossoms. All are very susceptible to frost. Look for begonia tubers at garden centers or order tubers/plants online from Longfield Gardens ( Also available are special begonia starting kits to order online:, and In late spring and early summer begonias are often found as potted plants in nurseries and garden centers.

Once you get to know these extroverted "girls," you are sure to become BFFs. The Netherlands Flower Bulb Information Center offers some tips for tuberous begonia success.

Begonia basics:

• Do not plant these tender bulbs out in the garden until the threat of frost has passed.

• Generally begonias take 12 to 15 weeks to bloom, and then continue to bloom until the season ends.

• For earlier bloom, start tubers indoors in pots (about six weeks prior to the last usual frost date).

• Begonias love soil that drains well and to grow in shaded locations out of the wind. Containers make it easier to control soil conditions and can be positioned to minimize sun exposure, heat and wind.

• Begonias do not like full sunlight.

Ideally begonias preform their best where:

• Day temperatures are warm, up to 90 degrees

• Night time temperatures are cool, around 55 degrees.

• Average humidity is 69 percent or above.

Starting Begonia Tubers:

• Select tubers that are firm to the touch.

• Start begonias indoors about six weeks before the local planting date, when the threat of night frosts is past.

• Plant in clean containers two to three inches deep with good drainage hole. Use a commercial potting soil mixed with peat moss and sand, so soil stays moist but not soggy.

• Place tubers in soil mix with convex side pressed gently into the soil surface. Cover with about a half inch of soil mix.

• A warm/humid setting is optimal for promoting growth. Keep soil moist, but not wet. Never let soil dry out completely.

• When shoots are 6- to 8-inches tall, transplant to the garden or outdoor containers.

Planting and Growing Tuberous Begonias:

• Plant tuberous begonias in well-drained, moisture-retentive soul with a high humus content. Space plants one per square foot, keeping in mind that begonias do not like hot sun. Keep away from direct sunlight, midday heat and out of the wind. Direct morning and late afternoon sun is O.K., but avoid windy areas. Wind can dry out plants. Hanging baskets are especially susceptible to being dried out in a windy location.

• Most upright-flowering plants will need staking.

• Depending on the size of the plant, an 8-inch pot is plenty big for one plant. Three begonias fit nicely into a 15-inch pot. • Keep soil moist, but do not over water. Water the soil only and not the plant. A light application of houseplant fertilizer is helpful for optimal performance, about once a month.

• For sturdier plants, pinch off extra or too-long stems when the plants are developing. Keep the strongest three stems and nip off any others. For fewer but bigger flowers, pinch off early-developing flowers until the plant reaches 10 inches tall.

• In the fall when night frosts hit, begonia season is over. Either bid begonias adieu as annuals, or prior to a killing frost, lift the tubers for over-winter storage. White Flower Farm suggests: Dig plants grown in the ground with a ball of soil and let them dry out in a shed or on the garage floor. When the stems break free from the tubers, shake off excess soil and allow the tubers to cure in the sun for about four days. Then store them in dry peat moss or sand in open flats in a cool (45 to 50 degrees F), dry place.

Don’t let begonias' reputation let you pass these beauties by. Frilly, fabulous tuberous begonias are sure to beguile you with their ease of culture and command performances in the shady garden whether in containers or in the ground. And there’s no time like the present to start tuberous begonias to light up shaded areas come summertime.

Lynette L. Walther is the recipient of the Garden Writers Association’s Silver Award of Achievement for 2012. She is a member of the Garden Writers Association, and she gardens in Camden. Got questions, or comments? Visit her blog, and join in the conversation at: or “friend her” on Facebook.


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