Annuals, Perennials, Shrubs
Grown for textured, multicolored foliage, saucer-size flowers, or lacy clusters of smaller blooms.
Grow as perennials in Zones 14–24, H1, and H2, except as noted. Can also be grown as annuals anywhere or dug and stored. Outdoors, most grow best in pots in the ground or in hanging baskets in filtered shade, with rich, porous, fast-draining soil, consistent but light feeding, and enough water to keep soil moist but not soggy. Most thrive as indoor plants, in a greenhouse, or under a lath. Some prefer terrarium conditions. Almost all require at least moderate humidity. In areas with hot, dry summers or indoors in winter, set pots in pebble-lined saucers or trays kept filled with water to below pot level.
Most are easily propagated from leaf, stem, or rhizome cuttings. They also grow from dust-fine seed. Of the many hundreds of species and varieties, relatively few are sold widely.
Best in Zones 4–6, 15–17, 21–24, and H1; possible in 7–9, 14, 18–28, 31, 32–with attention to humidity. Annuals in all but hot, dry climates. Among the best-known begonias are these magnificent large-flowered hybrids that grow from tubers. Members of this group range from plants with saucer-size flowers and a few upright stems to multistemmed hanging basket sorts covered in blossoms. With the exception of some rare kinds, they are summer and fall blooming.
Strains are sold as hanging or upright. The former bloom more profusely; the latter have larger flowers. Colors include almost everything but blue; shapes are frilly (carnation), formal double (camellia), and tight-centered (rose). Some have petal edges in contrasting colors (picotee). Popular strains include Double Trumpet (improved rose form), Prima Donna (improved camellia), and Hanging Sensation. Begonia boliviensis, cascading begonia, is a particularly lovely hanging type with profuse orange-red blooms.
Most gardeners grow tuberous begonias in containers. Buy dormant tubers (the bigger the better) in midwinter. Set them in pots filled with a rich, humusy soil mix, placing them indented side up and covering them with no more than 1/4 in. of mix. If you’re planting a number of tubers, it’s easiest to start them in a flat or shallow box, spacing them about 4 in. apart. Place pots or flats in a well-lit spot (but not in direct sun) where temperatures will remain above 65°F/18°C; keep soil moist but not saturated during the rooting period. When the tubers have produced two leaves, move them outside, weather permitting (night temperature must remain above 50°F/10°C); or pot up plants started in flats.
You can also plant begonias in the ground at this point; amend the existing soil, using 1 part soil to 2 parts potting mix. Choose a spot in filtered shade, such as under lath; or plant in an open area with eastern exposure. Water enough to keep soil moist but not soggy. For best bloom, mist with water several times a day unless you live in a cool or foggy area. Watch for fuzzy white spots on leaves; these signal powdery mildew. Begin feeding with liquid fertilizer a week or two after plants reach the two-leaf stage. For largest possible blooms, you can use a half-strength solution every other week, but monthly regular-strength feedings yield fine plants.
When leaves begin to yellow and wilt in fall, gradually reduce watering and stop fertilizing. When leaves fall off, lift tubers, shake off soil, and dry in a cool, dry spot for several days. Then store in a cool, dry place such as a shed or garage until spring; when small pink buds appear, plant the tubers once again. (You can also buy small seedling plants each year in early spring and plant them out in pots or in the ground.)
They get their name from their stems, which grow tall and woody and have prominent bamboolike joints. The group includes so-called angel-wing begonias. These erect plants have multiple stems, some reaching 5 ft. or more under the right conditions. Most bloom profusely from early spring through autumn, bearing large clusters of white, pink, orange, or red flowers. Some are everblooming. Among the many available varieties are ‘Bubbles’, with spotted foliage and pink, apple blossom-scented flowers; ‘Honeysuckle’, with plain green foliage and fragrant pink flowers; ‘Irene Nuss’, with dark red-and-green leaves and huge drooping clusters of coral pink flowers; and ‘Orange Rubra’, with medium green leaves, sometimes spotted with silver, and bright orange flowers.
When roots fill 4-in. pots, plants can be placed in large containers or in the ground. Position plants where they will get plenty of light, some sun, and no wind. They may require staking. Protect from heavy frosts. Old canes that have grown barren should be pruned back to two leaf joints in early spring to stimulate new growth.
B. grandis evansiana grows from a tuber to 2–3 ft. tall and wide, with branching red stems carrying large, smooth, coppery green leaves with red undersides. Summer flowers are pink or white, carried in drooping clusters. Tops die down after frost. In colder regions, mulch to protect roots.Begonia, Hiemalis
May be sold as Rieger begonias or Elatior hybrids. These profuse bloomers are outstanding outdoor or indoor plants. They form bushy, compact mounds to 1–1 1/2 ft. tall and 1 ft. wide. Flowers appear over a long season that includes winter. The 2-in. blooms come in white, yellow, orange, many shades of pink, and red; available in single and double forms. Frinzie series has white or apricot blooms with fringed, red-edged petals. Plants in the Solenia series are vigorous growers with large, full flowers.
Give indoor plants plenty of light in winter. In summer, keep out of hot noonday sun. Water thoroughly when top inch of soil is dry, but don’t sprinkle the leaves. Plants may get rangy, an indication of approaching dormancy; if they do, cut stems to 4-in. stubs.Begonia, Multiflora
These are essentially small-flowered, profuse-blooming tuberous begonias. They are bushy and compact plants to 1–1 1/2 ft. tall and wide, with profuse bloom in carmine, scarlet, orange, yellow, apricot, salmon, or pink. Includes the popular Nonstop and Pin Up strains.
With their bold, multicolored leaves, these are probably the most striking of all foliage begonias. While many named varieties are grown by collectors, easier-to-find unnamed seedling plants are almost as decorative.
The leaves grow from a rhizome; see “Rhizomatous begonias” for care. In addition, rex begonias need high humidity (at least 50 percent) to do their best. Provide it by misting with a spray bottle, placing pots on wet pebbles in a tray, or keeping plants in a greenhouse. When rhizome grows too far past edge of pot for your taste, either repot into a slightly larger container or cut off rhizome end inside pot edge. Old rhizome will branch and grow new leaves. Make rhizome cuttings of the piece you remove and root in mixture of half peat moss, half perlite.Begonia, Rhizomatous
Like rex begonias, these grow from a rhizome. Although some have handsome flowers, they are grown primarily for foliage, which varies widely in shape, color, and texture among species and varieties. Among the dozens of species and varieties in this group is the old favorite B. masoniana, called iron cross begonia; its large, puckered green leaves have a chocolate brown pattern resembling a Maltese cross.
Rhizomatous begonias perform well as houseplants: give them bright light and water only when the top inch or so of soil is dry. Plant them in wide, shallow pots. They flower from winter through summer, the season varying among specific plants. White to pink flowers appear in clusters on erect stems above the foliage. Rhizomes will grow over edge of pot, eventually forming a ball-shaped plant; if you wish, cut rhizomes back to pot. The old rhizome will branch and grow new leaves. Root the pieces of rhizome in a mixture of half peat moss, half perlite.
These bushy, compact plants grow as perennials in Zones 13–24; H1, H2 andas annuals anywhere. Dwarf (6–8-in.) and taller (10–12-in.) strains grown in garden beds or containers, producing lots of small flowers in a white-through-red range. Plants bloom from spring through fall (use as a winter annual in hottest-summer climates). Foliage can be green, red, bronze, or variegated. In mild-winter climates, can live for years. Thrive in full sun in cool-summer regions. Prefer broken shade in hotter climates, but dark-foliaged kinds will take sun if well watered.
This large class is marked by multiple stems that are soft and green rather than bamboo-like.They are grown for both foliage and flowers. The leaves are very interesting—some are heavily textured; others grow white or red “hairs”; still others develop a soft, felt-like coating. Most grow upright and bushy, but others are less erect and are well suited to hanging baskets. Flowers in shades of pink, red, white, or peach can come at any time, depending on species or variety.
Outstanding examples include fern-leaf begonia (B. foliosa), with inch-long leaves packed tightly on a twiggy plant for a fernlike look. Its long, drooping stems hold small white flowers nearly year-round in mild weather. Fuchsia begonia (sold as B. fuchsioides or B. foliosa miniata) has delicate stems to 2 1/2 ft. tall, with dangling rose-pink to rose-red flowers that resemble fuchsias. The sturdy, sun- and wind-tolerant ‘Richmondensis’ can reach 2 1/2 ft. tall and 3 ft. wide, with arching red stems and shiny, deep green leaves with red undersides. Its vivid pink to crimson or white flowers develop from darker buds nearly year-round.
Care consists of repotting into a larger container as the plant outgrows its pot. Water when soil begins to dry on surface. Prune to shape; pinch tips to encourage branching.Begonia, Trailing
These have stems that trail or climb, depending on how you train them. They bloom sporadically during warm weather and are well suited to hanging basket culture or planting in the ground where well protected. They need conditions similar to those for tuberous begonias, though trailing types are not lifted for storage. Examples include hybrid ‘Potpourri’, with strongly scented deep pink flowers, and one of its parents, B. solananthera, with glossy light green leaves and fragrant white flowers with red centers. B. glabra has trailing stems to 3 ft. long, with heart-shaped, bright green leaves and profuse white flowers in winter and spring.
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