Begonias are popular as annual bedding plants outdoors and as houseplants indoors. There are about 1500 different begonia species native to tropical regions worldwide, including Central and South America, Asia, and Africa. According to the American Begonia Society, there are seven different types of begonias – divided primarily based on their species and growth habit. All are tropical plants that prefer warm, humid conditions. All are sensitive to cold temperatures. While wax begonias and tuberous begonias are common landscape plants in Iowa, the rest are more commonly grown as houseplants.
Semperflorens or wax begonias (Begonia x semperflorens-cultorum) are the popular annual begonias grown in the home landscape. Leaves are smaller than most other types of begonias, and they are usually green or bronze/burgundy. Flowers are usually white, pink, or red. Single and double flower forms are available. Wax begonias are noted for their durability in the landscape – tolerating both part shade and full sun. While most begonias are not noted for their drought tolerance, wax begonias can be, once established.
Tuberous begonias (Begonia x tuberhydria) have larger, showy flowers in more diverse colors. Leaves are larger and more angular. There are trailing and upright forms of tuberous begonias, both of which are commonly planted in containers. These begonias have tuberous roots that require a short dormant period indoors in fall and winter. Afterward, they can be planted in March in containers, so plants are established before transferring outside in May. There are hybrids created by crossing tuberous begonias and wax begonias. These are called Rieger begonias (Begonia x heimalis), and they are noted for their showy, colorful flowers (much like tuberous begonias) and bright green leaves. Rieger begonias prefer slightly cooler growing temperatures than other types; therefore, you often see more of these begonias in garden centers and florists in late winter.
Rex begonias (Begonia rex) are a type of rhizomatous begonia commonly grown as an indoor plant. They are noted for their showy leaves instead of flowers. Leaves are often curled or contorted – including leaves that curl into a tight circle. Rex begonia cultivars are available in a dizzying array of leaf colors – including green, white, purple, silver, pink, maroon, lavender, black, and other combinations. You won’t miss the insignificant flowers on this lovely houseplant.
Cane-type begonias (Begonia coccinea, B. albo-picta, B. lubbersii, and several hybrids) grow from thick, upright, cane-like stems and fibrous roots. The stems are swollen at the nodes, resembling bamboo, hence the designation as cane type. They are usually grown as houseplants and include the prized angel wing and dragon wing begonias. Clusters of pink, white, or red flowers appear throughout the year and cascade from the ends of stems. Leaves are large, asymmetrical, spotted or variegated, and equally as attractive. This type is often considered the easiest type to grow indoors as cane-type begonias tend to be more adaptable to varying light or moisture levels.
As the name implies, rhizomatous begonias these begonias have rhizomes or are large, swollen root-like stems just beneath the surface of the soil. As you might expect, several stems emerge from the soil making these plants dense and lush houseplants. Many of these begonias are also noted for their large, showy, and colorful leaves. Leaves are typically mottled or marked with darker veining or variegation. Beefsteak has long been a popular cultivar of this type of begonia. While some will have showy flowers in spring, the flowers are often secondary.
Trailing begonias (Begonia boliviensis and hybrids) are ideal for hanging baskets as their stems and flowers spill over the basket’s edge. Flowers are abundant in spring or year-round (depending on cultivar), making for a beautiful display when kept in warm, humid, shady sites.
Shrub-type begonias (Begonia grandis) grow from multiple stems, resemble cane-type begonias, but can exceed 6 feet tall in ideal locations. They are not typically grown in containers, as many will become too large over time. These types are more commonly grown as landscape plants in Florida or other warmer locations.
General Care of Begonias
Most begonias have similar care requirements. They thrive in warm temperatures (ideally 60-80F indoors or outdoors) and with regular, consistent moisture. However, the roots will rot quickly when soils remain wet for long periods. They prefer bright light but are not suited for intense, direct sunlight. Indoor types do best in eastern windows with some bright morning light. Those types grown outdoors during the growing season do best in part shade with limited afternoon sun.
Lastly, begonias can be propagated by many methods. Stem cuttings are relatively easy to root in water or in perlite under mist. Many begonias (especially the houseplant types) can also be propagated by leaf section cuttings where pie-shaped wedges of leaves are placed on moist media, and new plantlets emerge from the cut edges. Few plants can be reliably propagated this way, further attesting to the uniqueness of the genus Begonia!
Additional gardening “B” words with links to HHPN resources.
Baptisia – Genus for false indigo, a spring-blooming perennial native to many parts of the Midwest (including Iowa). Baptisias for the home landscape
Bark – the outermost layer of tree trunks, often distinctive to species. Beauty and Basics of Bark
Basil – popular annual herb; often included in pesto. Basil publication at Extension Store
Bee – any of 3,500 to 4,000 species of insects in the Order Hymenoptera with 4 wings and branched or plumose hairs on the thorax; pollinators of flowers and garden crops while gathering nectar and pollen. The Sweet Lives of Honey Bees
Bulb – geophyte or swollen underground structure that assists in overwintering of several spring/summer blooming species like tulip or lily; Forcing spring-flowering bulbs
Bumble bee – any of 47 species of large, fuzzy bees found in North America; important pollinators for some garden crops. Bumble Bees of Iowa
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