Introduction
Few plants bring as much consistent, vibrant color to the shady corners of a garden as begonias. Whether you are mesmerized by the massive, rose-like blooms of tuberous varieties or the intricate, swirling patterns on Rex begonia foliage, these plants are a highlight of the summer season. At Longfield Gardens, we believe that the joy of gardening should last beyond the first frost. While begonias are tropical by nature and cannot survive freezing temperatures, you don't have to treat them as one-season wonders.
Learning how to winterize begonia plants is a rewarding way to preserve your favorite varieties and save money on next year’s garden. The process is straightforward and depends primarily on which type of begonia you are growing. This guide will walk you through the simple steps to identify your begonia type and prepare it for a successful winter rest or a cozy season indoors as a houseplant. With just a little bit of preparation, you can ensure your begonias return even bigger and better next year.
Identifying Your Begonia Type
Before you pick up your garden trowel or moving dolly, you must know which type of begonia you have. Because "begonia" is a broad category including over 1,800 species, different varieties require different winter care. The way the plant grows and its root structure determine whether it needs a period of complete dormancy or if it can continue growing on a sunny windowsill.
Tuberous Begonias
These are the showstoppers of the shade garden. Tuberous begonias (including the popular 'Non-Stop' series and 'Illumination' series) grow from a thick, potato-like underground structure called a tuber. They typically have large, fleshy stems and spectacular, multi-petaled flowers. Tuberous begonias require a period of dormancy to survive. In the winter, the top growth dies back, and the tuber rests until spring. If you leave these in the ground in most parts of the US, the frost will turn the tuber to mush.
Fibrous and Wax Begonias
Wax begonias are the classic bedding plants often found in public parks or lining garden paths. They have small, succulent leaves (green or bronze) and clusters of tiny red, white, or pink flowers. They have a standard, fibrous root system rather than a tuber. These do not go dormant. To winterize these, you must bring them inside as active houseplants.
Cane-Type and Angel Wing Begonias
These varieties are named for their long, upright stems that look a bit like bamboo. They often have decorative, spotted leaves shaped like wings. Like wax begonias, cane-types have fibrous roots and do not go dormant. They are very happy to transition into the home for the winter months.
Rex Begonias
Rex begonias are grown primarily for their incredible foliage. Their leaves can feature shades of silver, purple, pink, and deep green in stunning geometric patterns. These are also fibrous-rooted and do not go dormant. They are popular as year-round houseplants but are often moved outdoors to porches during the summer.
Key Takeaway: Always check the roots and growth habit. If there is a "potato" at the base, it's tuberous and needs dormancy. If the roots look like a web of thin hairs, it's fibrous and should stay awake indoors.
When to Start the Winterizing Process
Timing is the most important factor when learning how to winterize begonia plants. Because begonias are tropical, they have no natural defense against freezing temperatures. A single hard frost—where temperatures drop below 32°F for several hours—can damage the plant tissues beyond repair.
For tuberous begonias, the goal is to wait for the plant to tell you it's ready. As the days get shorter and nights get cooler in September and October, you will notice the leaves beginning to yellow. This is a natural signal that the plant is moving its energy from the leaves down into the tuber for storage. A very light frost that nips the leaves but doesn't freeze the ground can actually be helpful, as it triggers the final move into dormancy. However, you must dig them up before the ground itself freezes.
For Rex, Cane, and Wax begonias, you should bring them inside much earlier. These plants prefer temperatures above 50°F. Once the night temperatures consistently dip into the 40s, it is time to move them to their winter home. Moving them while the outdoor and indoor temperatures are still somewhat similar helps reduce transplant shock and leaf drop.
How to Winterize Tuberous Begonias for Dormancy
Tuberous begonias are the easiest to store because they don't take up any window space. You are essentially putting them into a "hibernation" state in a cool, dark corner of your basement or a closet. Follow these steps to ensure your tubers stay healthy and plump until spring.
Step 1: Curing the Plants
Once the foliage begins to yellow or has been touched by a light frost, stop watering the plant. If the begonia is in a pot, move it to a protected area like a porch or garage where it will stay dry. Let the soil dry out completely. This "curing" phase allows the stems to naturally detach from the tuber. Do not pull the stems off forcefully; wait until they become brittle or mushy and fall away with a gentle touch.
Step 2: Lifting the Tubers
If your begonias are in the ground, use a garden fork to gently lift the tuber. Dig several inches away from the base of the plant to avoid slicing the fleshy tuber. If they are in pots, you can simply tip the pot over and crumble away the dry soil.
Step 3: Cleaning and Drying
Gently brush off the excess soil with your hands. Do not wash the tubers with water, as excess moisture can lead to rot during storage. Place the tubers on a tray or a piece of cardboard in a warm, dry, and well-ventilated spot (away from direct sun) for about a week. This allows the outer skin to toughen up.
Step 4: Final Trimming
Once the tubers are dry, remove any remaining bits of dried stem or shriveled roots. At this stage, the tuber should look like a clean, brown, somewhat shriveled disc or ball.
Step 5: Packing for Storage
You want to keep the tubers in a medium that manages humidity—not too wet, not too dry.
- The Container: Use a cardboard box, a paper bag, or a plastic bin with holes drilled for ventilation.
- The Packing Material: Place the tubers in a bed of dry peat moss, vermiculite, perlite, or even shredded newspaper. Make sure the tubers are not touching each other; this prevents a single bad spot from spreading to the whole collection.
Step 6: Choosing a Storage Location
The ideal storage spot is cool, dark, and dry. Aim for a temperature between 40°F and 50°F. An unheated basement, a cool closet, or an insulated crawlspace works well. Avoid areas that might freeze, such as an uninsulated garage in a cold climate.
What to do next for tuberous begonias:
- Stop watering two weeks before you plan to dig.
- Label your tubers by color or variety name using a soft pencil or a tag.
- Set a monthly reminder on your calendar to check the tubers.
- If a tuber feels soft or mushy during a check, remove it immediately.
- If a tuber looks extremely shriveled, a very light mist of water on the packing material can help.
Winterizing Non-Dormant Begonias as Houseplants
If you have Wax, Rex, or Cane begonias, you are bringing a living plant into your home. This transition requires a bit more care to ensure the plant adapts to the lower light and drier air of an indoor environment.
Transitioning Indoors
The move from a lush outdoor garden to a climate-controlled house can be stressful. To make it easier, bring your plants inside for a few hours a day over the course of a week, or move them to a shaded porch first. This allows the leaves to adjust to lower light levels gradually.
The Pest Check
Before bringing any plant indoors, inspect it thoroughly for "hitchhikers." Look under the leaves and along the stems for aphids, mealybugs, or spider mites. A simple win is to give the plant a gentle spray with a garden hose to knock off any insects. You can also wipe the leaves with a damp cloth or use a mild insecticidal soap if necessary.
Lighting Needs
Indoors, begonias need "bright, indirect light." This means a spot near a window where they can see the sky but aren't being baked by direct, hot sun. An east-facing or west-facing window is usually perfect. If your leaves start to look "leggy" (long stems with lots of space between leaves), the plant is reaching for more light and might need a brighter spot or a simple LED grow light. For more guidance, see these begonia maintenance tips.
Managing Humidity
One of the biggest challenges for indoor begonias is the dry air caused by home heating systems. Rex begonias are particularly sensitive to low humidity and may develop crispy brown edges on their leaves.
You can create a "microclimate" for your plants using a pebble tray. Fill a shallow tray with small stones and add water until it is just below the top of the stones. Place your begonia pot on top of the stones. As the water evaporates, it creates a pocket of humid air around the plant. Just make sure the bottom of the pot isn't sitting directly in the water, as this can cause the roots to rot.
Watering and Fertilizing
Plants grow much slower in the winter, so they need less "fuel."
- Watering: Wait until the top inch of soil feels dry before watering. "Drainage" is the key here—ensure your pot has holes so water doesn't sit at the bottom.
- Fertilizing: Stop fertilizing your begonias in late fall. Wait until you see new growth in the spring before you start feeding them again with a balanced, water-soluble fertilizer.
"A common mistake is overwatering begonias in the winter. Think of it as a rest period; the plant needs just enough water to stay hydrated, not enough to grow vigorously."
Potting and Soil Basics for Indoor Success
If your begonias were growing in the ground and you want to bring them in, you must pot them up correctly. At Longfield Gardens, we always recommend using a high-quality, "soil-free" potting mix rather than garden soil.
Garden soil is too heavy for containers; it packs down tightly, which prevents air from reaching the roots and slows down drainage. A good potting mix usually contains peat moss or coconut coir, perlite, and vermiculite. This creates a light, fluffy environment where begonia roots can thrive.
When choosing a pot, ensure it has a drainage hole. If you have a beautiful decorative pot without a hole, use it as a "sleeve." Keep the begonia in a plain plastic nursery pot with holes, and set that inside the decorative container. When you water the plant, take the plastic pot to the sink, let it drain completely, and then place it back in the decorative one. This prevents "wet feet," which is the quickest way to lose a begonia.
Regional Variations: How Your Zone Affects Winterizing
Your local climate dictates how much effort you need to put into winterizing. In the United States, we use USDA Hardiness Zones to determine which plants can survive the winter outdoors.
Cold Climates (Zones 3-8)
In these regions, winterizing is mandatory. The ground will freeze, and any begonia left outside will perish. You must follow the steps for lifting tubers or bringing fibrous plants indoors before the first hard frost.
Moderate Climates (Zone 9)
In Zone 9, you are on the edge. Some begonias might survive a very mild winter with heavy mulching, but it is a gamble. If you have a particularly favorite variety, it is always safer to lift the tubers or bring the pots into a garage or porch for protection.
Warm Climates (Zones 10-11)
If you live in a tropical or semi-tropical area, you are in luck! Begonias can often stay in the ground year-round. However, even in warm zones, tuberous begonias may still appreciate a "rest." If they stop blooming and start to look tired in mid-winter, you can reduce watering and let them go dormant in place, or lift them to give the soil a break.
Troubleshooting Common Winter Issues
Even with the best care, you might run into a few hurdles while winterizing your begonias. Framing these as easy-to-fix adjustments rather than failures will keep your gardening experience enjoyable.
Leaf Drop
It is very common for begonias to drop some leaves when they first move indoors. This is the plant's way of adjusting to lower light. Do not panic and start overwatering. Simply pick up the fallen leaves to keep the soil surface clean and give the plant a few weeks to settle in.
Powdery Mildew
This looks like a dusting of white flour on the leaves. It often happens when air circulation is poor and humidity is high but stagnant. To fix this, ensure your plants aren't crowded too closely together. A small fan to move the air in the room can also help.
Rotting Tubers
If you check your stored tubers and find one that is soft or smells bad, it is likely rotting. This usually happens if the tuber wasn't dried (cured) enough before storage or if the storage area is too damp. Remove the affected tuber immediately so the rot doesn't spread. If the rot is small, you can sometimes cut it out with a clean knife, let the wound dry, and re-store it, but usually, it's best to start fresh with a healthy tuber.
Leggy Growth
If your indoor begonias are growing tall and skinny with tiny leaves, they aren't getting enough light. Move them to a brighter window. You can also "pinch back" the stems. Use your thumb and forefinger to snip off the very tip of a long stem; this encourages the plant to grow side branches and become bushier.
Winter Care Checklist:
- Monitor Moisture: Check soil weekly, but only water when dry.
- Watch the Temperature: Keep plants away from cold drafts or hot radiator vents.
- Maintain Cleanliness: Remove dead leaves or flowers to prevent mold.
- Rotate the Pot: Give the plant a quarter-turn every week so all sides get equal light.
Waking Up Your Begonias in Spring
The most exciting part of winterizing is seeing those first signs of life in the spring. For indoor houseplants, you will notice faster growth and more vibrant colors as the days get longer in March and April. You can begin fertilizing again at half-strength.
For stored tubers, start checking them for "eyes" or small pink buds in late February or March. Once you see these buds, it's time to wake them up:
- Potting: Place the tubers in a shallow tray or small pots filled with fresh, moist potting mix.
- Direction: Ensure the "indented" or hollow side of the tuber is facing up. This is where the stems will grow.
- Light and Heat: Place them in a warm (70°F) spot with bright light.
- Watering: Water sparingly at first. Once you see green leaves emerging, you can start watering more regularly.
Wait until the danger of frost has completely passed and the night temperatures are reliably above 50°F before moving your begonias back outdoors. Transition them slowly, just as you did when bringing them in, to avoid sunburn on the tender new leaves.
Conclusion
Winterizing your begonias is a simple, rewarding process that bridges the gap between gardening seasons. By taking a few moments in the fall to lift your tubers or find a cozy spot for your foliage plants, you ensure that the beauty of your garden lives on. At Longfield Gardens, we want every gardener to feel confident in preserving their plants. Whether you are storing tubers in a basement or enjoying a Rex begonia on your dining table, you are participating in a cycle of growth that makes the return of spring even more special.
- Identify whether your begonia needs dormancy (tuberous) or indoor care (fibrous).
- Always bring plants inside before the first hard frost.
- Use a light, well-draining potting mix for any begonias kept as houseplants.
- Check stored tubers monthly to ensure they remain firm and healthy.
"The effort you put into winterizing today is an investment in a more beautiful, more established garden tomorrow. With a little care, these tropical beauties can become long-term members of your plant family."
Start preparing your storage boxes and clearing your windowsills today. Your future self—and your begonias—will thank you when spring arrives. For more tips on plant care and high-quality bulbs, visit us at Longfield Gardens.
FAQ
Can I leave my tuberous begonias in their pots over the winter?
Yes, you can leave the tubers in their pots if the soil is completely dry. Move the pot to a cool, frost-free area like a basement. In the spring, it is best to repot the tuber in fresh soil to provide new nutrients for the growing season.
How do I know if my begonia tuber is still alive in storage?
A healthy tuber should feel firm, similar to a potato. If you gently scratch the surface with your fingernail and see light tan or white flesh underneath, it is alive. If the tuber is mushy, hollow, or shriveled to the point of being brittle, it has likely perished and should be discarded.
Should I prune my begonias before bringing them inside?
For tuberous begonias, you must wait for the stems to fall off naturally. For wax or cane begonias being kept as houseplants, you can prune them back by about one-third. This makes the plant more manageable indoors and encourages fuller, bushier growth when the plant settles into its new environment.
Do I need to water my stored begonia tubers?
Generally, no. The goal of storage is to keep the tuber dormant. However, if you live in an extremely dry climate and the tubers look severely shriveled, you can very lightly mist the packing material (peat moss or vermiculite) once during the winter. Avoid getting the tuber itself wet, as this can cause rot.
