Begonias
Begonias are a commonly used bedding plant that can provide striking color in the landscape throughout the year. The begonia family contains more than 1,800 species and hybrids , many of which are commonly grown as potted foliage plants.
Begonias generally fall into three groups: fibrous-rooted, rhizomatous, and tuberous. Fibrous-rooted and rhizomatous begonias tend to perform best in the Florida landscape or indoors.
Fibrous-Rooted Begonias
This category includes wax, cane-like, shrub, trailing, and thick-stemmed begonias. In the landscape, wax begonias (Semperflorens group) are most popular, with flowers that keep their rich color even during the summer. While considered annuals, they can often survive in the landscape for several years. There are numerous single- and double-flowered varieties in shades of red, pink, and white, with either bronze or green foliage. Popular and reliable, wax begonias thrive in sun or shade and perform well in landscape beds or containers. They are tender to the cold, so they should be planted in the spring, after the danger of frost has passed. In South Florida they can be planted in the fall as cool-season annuals.
Cane-Like Begonias
Cane-like begonias have stiff, upright stems that give them their common name, and produce year-round clusters of dangling flowers in shades of red, orange, pink, or white. Leaves are spotted, banded, or splotched with color, and wing shaped, giving them the once-common name ‘Angel Wing’ begonias.
Landscape favorites include ‘Torch’ (red flowers) and ‘Alba’ (ever-blooming white). ‘Sophie Cecile’ is a reluctant bloomer, but its robust, five-foot foliage makes it a landscape standout. For South Florida gardeners these plants provide year-round interest; however, in North Florida they usually die to the ground during the winter.
Rhizomatous Begonias
Rhizomatous begonias have thick rhizomes, a type of stem that grows along the ground or only somewhat upright. The flowers are held on stems above the foliage in late winter and spring. This type does best in South and Central Florida; North Florida gardeners get to see the fantastic blooms only if they grow these plants in containers or shady areas. Common types are the star begonia (Begonia heracleifolia), the water lily begonia (B. nelumbifolia), and hybrids such as the beefsteak begonia (Begonia x ‘Erythrophylla’) and ‘Passing Storm’ (Begonia x ‘Passing Storm’), which is grown mostly for its beautiful lavender foliage. Some rhizomatous begonias have leaves up to three feet in diameter and make wonderful substitutes for hostas in the landscape.
Rex Begonias
Rex begonias are a type of rhizomatous begonia that are known by their colorful foliage and easy growth. These plants grow best in Florida and other tropical climates since they originated from the tropical and subtropical regions of India. They are great additions to landscapes for dimension and vibrant foliage.
Rex begonias leaves come in a wide variety of colors and although they are referred to as foliage plants, they also produce small white and pink flowers. They typically have a dense, round structure and can reach heights of up to 24 inches, making them an excellent choice for indoor home landscaping . These plants have alternate leaf arrangements with simple leaves that stem from a rhizome beneath the soil. It is important to note that the underground parts of rex begonia plants contain calcium oxalate, which can be toxic to pets.
Planting and Care
Begonias can be used in mass plantings, or they can be mixed with other annuals. Plant them as soon as possible after purchase. These easy-to-grow plants prefer warm temperatures, humidity, and moist, well-drained soil. When choosing a spot for a landscape begonia, look for an area that receives several hours of morning sun; many begonias can tolerate more sunlight if they are kept moist (but not too wet). Well-drained soil is particularly important as begonias will rot if they are overwatered or planted in an area that stays wet.
Your plants should be fertilized several times a year with a controlled-release fertilizer for best results. If your begonia gets leggy, don’t be afraid to cut it back. An occasional light pruning will also stimulate new growth and more flowers.
These tropical plants can be grown in USDA Hardiness Zones 8b to 11. If you live in a cooler part of the state, be sure to protect your outdoor begonias from frost. They also thrive indoors. Potential pests you may encounter include mites, mealybugs, scale, whiteflies, nematodes, and slugs/snails. Diseases that begonias are prone to include bacterial leaf spot, powdery mildew, botrytis, Pythium root rot, and rhizoctonia crown rot. To prevent these issues, make sure to choose only healthy plants, have proper air circulation, use clean tools for pruning, and water appropriately. Contact your county Extension office if you encounter any problems.
Propagation
Begonias are easily propagated at home from leaves, stems, rhizome or tuber cuttings, as well as by seed. Stem cuttings are very simple. A stem cutting should be two to four inches in length and come from a healthy plant. You can root these cuttings in moist perlite, potting soil, or any other sterile media. Some begonias will also start from leaf cuttings. The only requirement is that the leaf portion contains a main vein. With both stem and leaf cuttings, you should keep them in a cool, humid environment until they root. You can also divide some varieties of begonia by simply separating the stems. Once rooted, take each section and plant them in clean potting media.
For more information about propagating begonias, read this Ask IFAS publication, “A Beginner’s Guide to Begonias: Vegetative Propagation.”
New Cultivars
Breeders are continuously producing new cultivars of begonias, many of which are interspecific hybrids of the ones discussed above. These tend to be very vigorous with larger leaves and bigger blooms. Examples include the BIG® series which resemble wax begonias on steroids and Dragon Wing®, a cane-type that’s sterile so more energy is diverted to flowers instead of seeds. For more information, visit the American Begonia Society’s website and consider visiting a meeting of one of the state branches to see what a fantastic array of begonias you can grow in Florida.