Growing Tips: Tuberous Begonias
OVERVIEW
While there are many types of begonias, often grown as houseplants for their stunning foliage, tuberous begonias are grown for their large, showy flowers that can bring color to shaded patios or porches and to shady areas in the garden.
Tuberous begonias are grown from tubers that can be lifted and stored each year like dahlias and other cold-sensitive tubers.
SITE SELECTION
Begonias prefer temps above 60 degrees, however they will show signs of stress when temperatures reach 80+ degrees. In areas with very hot summers, make sure begonias are well watered and planted in shady areas. Prefers humidity, so these begonias will thrive in humid environments as long as they are shaded from high heat.
Begonias require bright, indirect light or part shade. Avoid direct midday sun, as this will scorch the plants. Soil should be light and enriched with organic matter.
PLANTING
- Tubers should be firm and pest free. Often small pink buds will begin forming as temperatures warm.
- Tubers can be sterilized by soaking for 15 minutes in a solution of 10 parts cold water to one part bleach, though this is not required for viability.
- Plant tubers just below the surface with the indented side facing up. Water in well.
- To get a jump on the season, plant in late winter/early spring indoors and transplant outside when temperatures warm and all threat of frost has passed.
SPRING/SUMMER CARE
- Plant out after all danger of frost has passed.
- Keep moist but not soggy. If too wet, the tubers will rot.
- Heavy feeders during the growing season that will benefit from a feeding every 2 - 4 weeks with a balanced, diluted fertilizer.
- Remove spent blooms and yellowing leaves to encourage more blooms. Tend to be prolific bloomers, so you should have blooms throughout the season.
FALL/WINTER CARE
- Lift before first frost, cut back and remaining leaves/flowers, and store in a cool dry location for next year.
- Store in peat moss, wood shavings or other medium that will keep bulbs insulated but discourage rotting or disease.
OTHER CARE TIPS
- Many varieties of begonia are toxic to pets, so be mindful of what may roam around your begonias when you decide on a location. Outdoor hanging baskets will help keep them away from all but the most determined cats. Deer and rabbits generally avoid begonias for this reason.
- Stems tend to be fleshy and breakable; be careful when transplanting. (They will bounce back from broken stems fairly quickly, so don't panic if you lose a stem from an otherwise healthy and vigorous plant.)
- Susceptible to a variety of pests and diseases. Be on the lookout for powdery mildew, botrytis, and pests like aphids in particular. Ensure good air circulation and plant near pest deterrents such as herbs that can tolerate part shade.