How to Store Tuberous Begonias for Winter and Restart Them in Spring
Let me begin by saying I am a perennial kind of gardener. I love when my day lilies, tiger lilies, and hostas just pop up every year. But on Mother's Day, my sister gave me a gorgeous, potted tuberous begonia that grew and bloomed all summer. I've never been so fascinated by a plant. It's been such a joy to watch it thrive! It has the most gorgeous orange blooms!
In this article, I will show you how to overwinter this annual flower safely by digging it up before the killing frosts and storing its tubers during the coldest months of the year. That way, you can easily restart your lovely begonias the following spring.
When Should You Think About Storing Your Tuberous Begonias for the Winter?
In northern climates where it freezes, the tuberous begonia must be dug up and the tubers stored indoors for the winter. This should be done after the first light frost.
In southern climates where it rarely or never freezes, tuberous begonias will go dormant on their own. They do this according to the length of the day. This usually occurs in October or November. Stop watering them when they start to yellow and their leaves drop. Even in relatively warmer climates, however, it is often still advisable to dig up your begonias and store them for the winter.
Note: If your begonias were potted and not in beds, you can put the pots in an indoor place where the tubers won't get wet. The problem is that they are more likely to rot if they remain buried in soil. You may be more successful if you dig them up, dry them out, and store them.
How to Overwinter Your Tuberous Begonias
When the time comes to dig up your begonias, simply follow these easy steps:
- Gradually decrease the amount of water you give your begonias and stop fertilizing them by the end of August.
- Once the leaves begin to turn yellow—or after the first killing frost—dig up the entire plant and its tuber.
- Gently remove all soil and loose roots.
- Lay the entire plant in a warm, dry area for several days to thoroughly dry it out.
- Once it is dry, remove the stems and any remaining foliage, also being sure to shake off any excess soil.
How to Store Begonia Tubers
Place each tuber in a separate paper bag, and place them in a cool, dark place like a cardboard box for storage. Basements and garages are often great places for extended storage. The temperature range should ideally be between 40–50°F. This will allow the tubers to breathe and will prevent rotting and pests.
You should also periodically check in on the tubers and discard any that show significant symptoms of withering or rot. As long as they are separated, however, a problem that occurs for one tuber will not affect them all.
I only had one tuber, and I placed it on a newspaper on a shelf in a dark, dry storage room in the basement. The dirt and leaves fell away as it dried out. My tuber is now sprouting buds!
How to Restart Begonia Tubers in the Spring
When you plan to restart your begonias, it's best to get started in late winter or early spring. Tubers planted in February should bloom around June, while tubers started in March or April should bloom around July. It's also important that the sprouts appear before planting. Here is a helpful guide:
- Fill a nursery flat or another shallow container with planting medium. Well-rotted leaf mulch is recommended. Just make sure the medium is loose, well drained, and does not contain fertilizer or manure.
- Loosen the soil and space the sprouted tubers evenly 4–6 inches apart, laying them in flat. The indented side of the tuber should be facing up. The roots develop from the top and the sides. Don't completely bury the tuber, however. Just cover it lightly with the planting medium.
- Water thoroughly, but lightly. (Tubers are quite susceptible to rot during this time, so it's important to keep the medium fairly moist, but not wet. The tubers should never be in standing water, and you don't want to let water accumulate in the hollow part of the tuber.)
- Place flat in a warm place with filtered sunlight and partial shade.
- Keep them indoors until the weather warms during the day. You can then place them outside in partial shade. The hotter the climate, the more shade they will prefer.
Keep the tubers in flats until the roots are well developed. You can transplant them in pots or flower beds when there is 4–5 inches of growth.
Water them only when the soil begins to show dryness. You can water more as the plants develop.
Note: For more information on how to grow and care for this wonderful plant, check out this helpful guide on How to Care for Tuberous Begonias.
What Are Tuberous Begonias?
Tuberous begonias (begonia tuberhybrida) are a hybrid species of begonias grown from tubers. They were created through years of cross-breeding and development. Here are just some of their distinctive features:
- Their flowers come in many shapes, sizes, and colors. They can be single- or double-petaled, ruffled, scented, or multicolored.
- They can stand upright or be used in hanging baskets.
- They can have frilled, ruffled, or plain petals or rose-shaped blooms.
- Three blooms develop on each stem.
- The male flowers are usually double petaled and can be quite large and beautiful.
- The two outer blooms are usually female. They are smaller—but still quite beautiful—and are single petaled with a light green seed capsule behind the petals.
Though they are generally only hardy in USDA zones 9 to 11, tuberous begonias are quite easy to take care of. They endure the elements of wind and rain and greatly enhance your garden from June through October. Some types of tuberous begonias include: Panorama, Illumination, Pin Ups, Ornament, On Top, Non-Stop, and Charisma series.
Their winter dormant period is determined by day length and weather in cold climates and day length in warmer climates. They need to follow their natural cycle, and the above information will help you let them to do that.
What Kind of Soil Do Tuberous Begonias Need?
Tuberous begonias can survive in many types of soil. The most important thing is perfect drainage, as they need to be able to shed excess water in order to avoid root rot. But while they need well-drained soil, they are not drought tolerant. So it is important to check in on the moisture level of their soil, particularly during long gaps between rainfalls.
If you are planting the tubers outdoors, prepare the garden soil. Large amounts of peat moss are not recommended, except in sandy soils. Clay soil drains poorly. So add humus, sand, or both.
If you would like to make your own soil, the best mix would be:
- 4 parts well-decayed mulch
- 1 part garden loam
- 1 part course sand
Do not use a "potting mix". You can use a good potting soil from a nursery though. Just make sure it contains humus.
Check Your Soil Often
Though begonias need well-drained soil, they are not drought tolerant. So be sure to periodically check on the moisture level of your soil, especially during long gaps between rainfalls.
What Are Some Other Ways to Propagate Begonias?
Though restarting your begonias from tubers may be one of the easiest options, you can also propagate them using other methods. While trying to start begonias from seeds can be notoriously difficult, these two methods of asexual propagation are quite easy:
Propagating Begonias From Stem Cuttings
- Snip a few stems just below the nodes. Cut them to about 4 inches in length.
- Carefully strip the leaves from the bottom half of the stem.
- If you have rooting hormone, go ahead and dip your cuttings in them now.
- Make a hole in your growing medium (soil/peat moss/vermiculite/perlite) and insert your cutting.
- Keep your medium moist and the air humid, and you should have a tiny plant in a few weeks.
Propagating Begonias From Leaves
- Snip a mature leaf from your plant, leaving about an inch of petiole.
- Insert the petiole into a growing medium (soil/peat moss/vermiculite/perlite).
- Once again, keep your medium moist and the air humid, and you'll have a tiny plant in no time.
Note: If you want to help keep the humidity up, you can cover the stem or leaf cutting with a transparent plastic bag and place it in a moderately sunny location.
Frequently Asked Questions
Here are a handful of answers to frequently asked questions related to begonias and how to care for them:
What type of begonia do I have?
This simple guide should help you identify which of the three main types of begonias you might have:
- Tuberous: These are complex hybrids that span across many species, developed over many years through careful breeding. Their most notable characteristic is their fleshy tubers, which are roots that store energy for the plant to draw from during its dormancy in winter. In addition to hybrids, this category also includes the Bolivian, Hiemalis, Lorraine or "Christmas," and semi-tuberous varieties.
- Rhizomatous: This is the largest category of begonias. If the foliage on your plants have spectacular colors in vibrant patterns that tend to overshadow their smaller blooms, they're likely to be of the rhizomatous type. The roots of these types of begonias come in the form of fleshy rhizomes that creep across the surface of the soil. This category also includes rex begonias that are often grown for their amazing foliage that come in vivid colors like green, red, silver, purple, brown, and pink.
- Fibrous-Rooted: Although all begonias have fibrous roots, if you don't see either tubers or rhizomes, they likely belong to this category. A few major subdivisions exist within this variety. The "wax leaf" type can be identified by its glossy leaves shaped somewhat like spoons and are often grown from seeds (though they can also be grown from cuttings or by division). The "cane stem" or "angel wing" type stands out through its elongated, erect canes that often reach 2–3 feet long (but can extend as high as 12 feet). The leaves of this variety are often purple, red, or speckled with silver, while the flowers tend to be pink, red, or white.
How do you protect tuberous begonias from diseases, rot, and pests?
- Powdery mildew: Identified by white powdery spots on all sides of the leaves and greasy spots on the undersides of them, this disease can be prevented by adequately spacing out your plants by at least 12 inches. This allows them to benefit from proper air circulation.
- Bacterial leaf spot: Dark, necrotic, water-soaked spots on your leaves indicate this fatal disease caused by microorganisms thriving in wet, cool conditions. Avoiding overhead watering. Discarding infected leaves early should help you easily manage this ailment.
- Root and stem rot: If your tubers begin to look discolored or your stems start turning black, your begonias may be suffering from rot caused by fungi. The problem is fairly easy to address, however, by ensuring that your soil drains well and never becomes waterlogged.
- Insects and other pests: Aphids and thrips are the two most common pests for begonias, sometimes further complicating matters by transmitting additional diseases like spotted wilt virus (which stunts growth, diminishes the quality and health of flowers, and leaves spots or rings on leaves). You can reduce the presence of thrips by keeping susceptible plants like dahlias away from your begonias. Aphids can be reduced by hand-picking or by applying insecticidal soap, which also happens to work well for controlling gnats, whiteflies, mealybugs, and spider mites. And if you notice problems with slugs or snails, consider hand-picking them or setting out some slug or snail bait.
How do freezing temperatures affect tuberous begonias?
If tuberous begonias are exposed to freezing temperatures for extended periods of time, the portions of the plants that are above the ground will die. But in the spring, the plant will regrow from its underground tubers that stay dormant throughout the winter. These begonias will also produce new tubers during the growing season that will then fall to the ground in autumn. These new tubers will then sprout in the spring.
- MacKenzie, Jill and Moncada, Kristine. Tuberous Begonias. University of Minnesota Extension. Retrieved on 26 October 2018.
- Hodgson, Larry. Multiplying Begonias. Laidback Gardener. Retrieved on 26 October 2018.
- Barth, Brian. How to Identify a Begonia. SF Gate. Retrieved on 29 October 2018.
- Evans, Judith. Tuberous Begonia Problems. SF Gate. Retrieved on 29 October 2018.
- Rhoades, Jackie. Tips on Propagating Begonias From Cuttings. Gardening Know How. Retrieved on 31 October 2018.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
Questions & Answers
Can I store begonias that have been grown from seeds?
I had tuberous begonias and was able to dry and replant the tubers. If you planted your begonias from seeds, the female Begonia plants have seed pods at the base of the flower. The pod can be removed when it appears to be dried or drying up. The seeds can be removed and dried and saved in a container or envelope for replanting.Helpful 23
Can I leave my tuberous Begonias in an unheated garage for the winter?
Yes, that should be fine.Helpful 19
Can I keep my dormant tuberous begonias in flower pots and put a bag over them?
I don't think so because they have to dry out and sprout again before planting.Helpful 8