By Erin Marissa Russell
First things first: Wax begonias are a category of begonia plants (Begonia x semperflorens-cultorum) with fibrous roots, as distinguished from begonias with tuberous roots. Wax begonias are especially known for their ability to flourish during times of drought or heat. Wax begonias may have bronze or green leaves, and the bronze-leaved varieties are better suited for sunshine. We’ll delve into this and other things you need to know to take care of wax begonias in this article.
Wax begonias are known for the beauty of their floral display, which lasts all summer long and into the early days of fall. Their growth habit is attractively bushy and can reach heights of up to 18 inches. However, most stay between six inches and one foot tall, with the same spread. Plants are made up of heart-shaped leaves that appear to be covered in shiny wax. The foliage may be green, reddish bronze, or deep brown, with pink, red, or white blossoms.
Ambassador Series: Wax begonias in this group are known for their large blossoms, green foliage, and compact growth.
Cocktail Series: Plants in this series are dwarf varieties that grow to between six and eight inches tall. Foliage is bronze, and blooms may be pink, white, red, or white edged in red.
Doublet Series: As the name suggests, wax begonias in this series are known for their showy double blooms.
Pizzazz Series: Choose from pink, red, or white blooms in this series, which is known for producing lots of flowers. These wax begonias grow to between eight and 10 inches tall.
Prelude Series: This strain is especially hardy in rainy or hot climates. They’re known for their compact growth and shiny, vivid green leaves.
Super Olympia Series: These varieties have glossy green leaves and are known for the bright colors of their large flowers, which appear early in the garden. Choose from shades including pink, rose, red, and white.
Victory Series: These bronze-leaved wax begonias are known for the size of their blossoms. Available in pink, red, and white.
When you’re considering where to plant your wax begonias, you need to take the soil and the sun exposure into account. Do take into account the care needs of the individual variety of begonias you are growing, as there is some discrepancy between the types. Generally, however, most begonias grow their best when given partial shade, which translates to between three and six hours of direct sunshine each day. As far as soil is concerned, give begonias moist soil that contains plenty of rich organic material and provides good drainage.
Begonias can be a bit finicky when it comes to lighting, needing a Goldilocks-like “just right” amount to really thrive. Most begonias need access to some direct sunlight in order to blossom their best. However, too much direct sunlight, or sunlight that is too bright, can scorch the foliage of some begonia varieties.
Check into the sun exposure needs of the variety of wax begonias you are growing to ensure you provide them with just what they need. As a rule of thumb, begonias that have bronze leaves are better able to handle full sun than green-leaved begonias. If you are growing begonias with green leaves, try to plant them in a spot where they will get sun in the morning and shade in the afternoon to prevent sunscald on their leaves.
You can start wax begonias from seed or from small plants. Start your seeds indoors about 12 weeks before moving them into the garden, which should take place after all danger of frost has passed. Sprinkle the seeds on top of the soil and do not cover them. Keep them between 68 and 75 degrees Fahrenheit.
Wax begonia seeds are so tiny that they are sometimes sold as pellets to make them easier to handle. If the seed you want to use is pelleted, follow the instructions on the packaging for planting for best results.
Whether you are planting small plants from the nursery in the garden or transplanting seedlings you have started indoors, situate the young plants about 6 to 8 inches apart.
Be mindful when watering begonias not to splash water on the foliage, as this can lead to sunscald as well. Aim the stream of water at the base of the plant where the roots are. The best time to water begonias (and most plants in the garden) is in the morning. Watering should be avoided when the sun is shining directly on the begonia’s leaves.
Wax begonias are relatively low maintenance because they are “self-cleaning” plants. This means the blossoms will fall from the plant naturally at the end of their life cycle, so you won’t have to spend time deadheading and picking off the spent blooms.
Wax begonias benefit from an application of mulch during the summertime to keep the roots moist and cool.
Wax begonias are grown as annuals, but if you choose to grow yours in containers, you can cut them back in the fall and bring them indoors to spend the winter in comfort. Keep them in a place where they will stay cool, and reduce watering as the plants will go into dormancy. Wax begonias prefer small containers and a peat-based rich potting mix that drains well. Repotting should only be needed a time or two during the plant’s life, as wax begonias prefer to stay rootbound. That said, repotting should be done in springtime, slightly increasing the size of the container and using fresh potting soil.
Wax begonias should not be propagated by seed collection, as they are almost all F1 hybrids that will not breed true to type. Instead, wax begonias should be propagated with leaf or stem cuttings taken in springtime. Choose cuttings that have at least two nodes but do not have blossoms, and make sure to use sterile, sharp gardening shears. Bury the cut end of the stem in moist potting soil and keep in a warm spot that offers some shade until it begins to produce new growth. Then it can be moved into its regular spot in the garden.
Pests and Diseases of Wax Begonia Plants
As charming and versatile as wax begonias are, these lovely plants can sometimes face a few challenges in the garden. By understanding the potential issues and learning how to prevent or address them, you can ensure that your wax begonias thrive and maintain their vibrant beauty throughout the season.
Powdery Mildew: One common problem that wax begonias may encounter is powdery mildew, a fungal disease that manifests as a white, powdery substance on the leaves. This can result in discolored, distorted foliage and, in severe cases, may cause the plant to wither. To prevent powdery mildew, make sure your wax begonias have proper air circulation and avoid overhead watering. If you notice signs of the disease, consider using a fungicide or homemade solution like a diluted milk spray to treat the affected plants. For more information, see our article Identify, Prevent, and Treat Garden Problems: Powdery Mildew Fungal Disease.
Stem and Root Rot: Wax begonias are susceptible to stem and root rot, which is often caused by overwatering or poorly draining soil. Symptoms of this issue include wilting, yellowing leaves, and blackened stems or roots. To prevent rot, ensure that your plants are grown in well-draining soil and water them only when the soil feels dry to the touch. If you suspect that your wax begonias are affected, it may be necessary to remove and discard the infected plants to prevent the disease from spreading. For more information, see our article How to Fight Stem and Root Rot.
Pests: Like many plants, wax begonias can attract certain pests, such as aphids, whiteflies, and mealybugs. These tiny insects feed on the plant’s sap, leading to distorted leaves, stunted growth, and potential disease transmission. To keep these pests at bay, regularly inspect your plants for signs of infestation and consider using insecticidal soap or other organic pest control methods if needed.
Sunscald: While wax begonias can tolerate a range of light conditions, too much direct sunlight can cause sunscald, resulting in pale, bleached leaves or brown, scorched spots. To prevent sunscald, provide your wax begonias with dappled sunlight or morning sun, followed by afternoon shade, especially in hotter climates. If your plants show signs of sunscald, consider relocating them to a more suitable spot or providing them with some protective shade during the hottest parts of the day.
Here are some other specific problems to look out for.
Bacterial Leaf Spot and Blight: For more information, see our article Tomato Diseases: How to Fight Bacterial Spot.
Botrytis: For more information, see our article Dealing With Botrytis Blight, or “Grey Mold” Fungus.
Mealybugs: For more information, see our article How to Fight Mealybugs.
Nematodes: For more information, see our article How to Fight Root Knot Nematodes.
Scale: For more information, see our article How to Control Scale Insects.
Slugs and Snails: For more information, see our article How to Control Snails and Slugs.
Thrips: For more information, see our article How to Fight Thrips.
Whiteflies: For more information, see our article How to Fight Whiteflies.
By staying vigilant and taking the proper preventative measures, you can minimize these common wax begonia problems and enjoy the lush, colorful display that these delightful plants bring to your garden.
Wax begonias are lovely in planters, window boxes, large plantings, or at the front of garden beds. Choose your favorite variety (or varieties) to grow and you’re on your way to enjoying their beautiful blooms.