GARDENING : Beguiling Begonias : Plants Are a Little Fussy About Food, Water, but They Love to Show Off, Indoors and Out
The vivid colors and showy flowers of tuberous begonias add brightness to shady patios or garden nooks. In recent years, the development of a variety called ‘Nonstop’ has helped popularize these shrubby plants, which have an undeserved reputation for being hard to grow.
“With the right circumstances and care, tuberous begonias, especially the ‘Nonstop’ variety, grow very well here in Orange County,” said Wade Roberts, garden director for Sherman Library and Gardens in Corona del Mar.
Sherman Gardens includes colorful begonias in its plant collection, and they’re in full bloom now.
“The most common mistake people make is over watering them, and that frequently causes root rot,” he added. “For that reason, I recommend growing tuberous begonias only in baskets so the water drains out.”
Tuberous begonias are so named because they are grown from tubers. Dormant in winter, they sprout buds in spring and flower continuously from summer through fall. The multiflora begonias, which include ‘Nonstop,’ produce many blooms and can continue flowering into November or December.
The older forms of tuberous begonias feature larger flowers, usually on a taller plant that might require staking. They are not as hardy as ‘Nonstop’ and are less tolerant of heat. Colors of begonias include bright white, yellow, orange, peach, pink, rose, brilliant red and dark red. Some of the older strains have picotee markings--a flower edged with another color. Recently, a picotee named ‘Pin-Up’ was hybridized in the ‘Nonstop’ strain.
Tuberous begonias require a shady location that receives bright light, good air circulation, consistent fertilizing, judicious watering and grooming to remove the spent blossoms. ‘Nonstops’ can tolerate more heat than other strains of tuberous begonias but still need protection from the sun, especially in inland areas.
They can be susceptible to powdery mildew, especially near the coast, and good air circulation helps reduce disease. Removing the old flowers will encourage the plant to produce more blossoms, and regular feedings will promote healthy growth and abundant blooms.
“Begonias are heavy feeders, and for best bloom production should be fed every two weeks,” Roberts said.
He recommends a high nitrogen plant food with a 10-10-5 formula early in the season. For best results, he alternates bimonthly with a high-bloom, lower nitrogen formula to encourage more flowers and less rampant plant growth. Fish emulsion can also be applied during the growing season.
“You can tell if you’re feeding correctly by examining the leaves,” he said. “There should be a nice roll to the leaf with a meaty thickness. The leaf color should be dark green, but not blue-green. If the plant’s leaves are light green, or the leaves don’t roll, the plant isn’t receiving enough food.”
Begonias need fast-draining soil high in humus. Roberts has devised a special mix for the tuberous begonias grown at Sherman Gardens. He uses 40% standard potting mix, 20% redwood compost, 20% orchid bark and 20% sponge rock. The resulting mix provides good drainage and aeration.
The vividly colorful flowering plants can only be grown outdoors but can be used as indoor centerpieces for a special occasion. The pots can be placed in decorative containers to grace a table and then returned to their customary outdoor location the next day.
In late fall, when bloom production stops and the leaves yellow and fall off, the plants can be forced into dormancy by withholding fertilizer and water.
“Stop fertilizing in September, and put the plants still in their containers in a dark corner and just forget about them for several months,” Roberts said. “A garage or basement is a good location. Although it may seem that the plant has died, it’s become dormant. In spring, tiny pink buds will swell on the tubers and the cycle of watering and feeding can begin again.”
Tuberous begonias grown in the ground should be lifted in fall. Shake off the dirt, dry the tuber in the sun for several days and store in a cool, dry and dark place. (If they’re left in the ground over the winter, they’ll usually rot.)
You can buy tuberous begonias in hanging baskets or pots in many local nurseries and garden centers. But for a novel experience, try a “dig your own” nursery--Weidner’s Gardens, 695 Normandy Road, Encinitas.
Weidner’s grows 10,000 begonias and encourages customers to bring their own containers and pot their plants directly from the growing fields.
“There’s less stress to the plant if it’s only transplanted one time,” Peggy Bobo, retail manager, explained.
Weidner’s does sell pots and provides cardboard boxes for transporting if anyone forgets them. It also carries a large selection of indoor plants and other flowering plants.
Plant prices range from $3.50 for the dig-your-own tuberous begonias to $10.50 for eight-inch hanging baskets. The store is open seven days weekly from 9:30 a.m. to 5 p.m.
Weidner’s can be a fun place for a family outing. The children can amuse themselves in the petting zoo, and there’s a picnic area.
Today and Sunday, Evelyn Weidner will conduct free classes on “Five Steps to Better Gardening,” at 11 a.m. and 2 p.m. She’ll share some of her secrets for growing great begonias.
Sherman Library and Gardens will hold a begonia workshop on July 8 from 9:30 a.m. to noon. Horticultural expert Christen Fusano will demonstrate and explain details of begonia culture, including soil mix, fertilizing, mildew control and propagation. Preregistration is required.
For information, call Sherman Gardens, (714) 673-2261.
