11 Common Problems With Flowering Begonia Plants

If your begonias are struggling this season, you've come to the right place! Begonias can have many common issues during their lifespan, so it's important to identify common problems early and remedy them as fast as possible. In this article, certified master gardener Laura Elsner looks at the most common issues that plague begonias, and how to fix them.

begonia problems

Begonias are no longer just the flower’s in your granny’s garden. There are so many types and varieties of begonias that it is no wonder they’ve been making a resurgence in both indoor and outdoor gardens. Of course, like with all plants, things can go awry.

Begonias are well known for being low-maintenance flowers. It’s one of the reasons they are so appealing, no matter how your begonias are grown. Unfortunately, many gardeners mistake low-maintenance with “no maintenance” and that’s where problems start.

If your begonia has started to struggle, or you’ve run into some issues with your plant and aren’t sure what to do, you’ve come to the right place. Follow along as we dig into the most common problems with begonias, and how to fix them!

Not Blooming

This is a big one. When your begonias aren’t blooming, this usually signals that there’s something wrong with the plant. There could be a variety of different issues that cause a lack of blooms. Let’s look at the most common three, which include type of plant, lack of sun, or overwatering your plant.

Variety

Top view, close-up of a garden with flowering begonias in white and bright pink. The leaves are alternate, heart-shaped, asymmetrical, dark green in color. The flowers are small, consist of several elongated petals and there are a lot of them - 3 flowers are grouped on cluster-shaped inflorescences. Flowers bloom in full sun in the garden.
If you want bright blooming flowers, then choose waxy or tuberous varieties.

I am going to get a more obvious reason out of the way first. Some varieties of begonias are known for their blooms, while others are prized for their foliage. Wax and tuberous varieties are the begonias we typically prize for their blossoms.

Rhizomatous varieties are more prized for their foliage. Rhizomatous begonias include rex begonias, which have gorgeous foliage, and smaller, less showy, blossoms for the most part. So if blossoms are what you are after, choose a wax, tuberous, or a combination of the two, known as a rieger begonia.

A good guide to follow is to purchase flowering begonias in the bedding out plants section of a garden center. Look for foliage focused begonias in the houseplant or tropical section of the garden center.

Not Enough Sunlight

Close-up of bright red tuberous begonia flowers blooming in a garden in full sun. The leaves are dark green, pointed, prickly at the edges. The flowers consist of several elongated petals, slightly reminiscent of a rosebud. Some red buds are not open yet. The background is blurry.
Although they are considered shade-tolerant plants, they require a minimum of 4-6 hours of sun to bloom.

While begonias are shade plants, too much shade will cause them to stop blooming. You want at least 4-6 hours of sun on them.

Any less and they will cease to bloom, or have far fewer flowers then they would in more sun. If you do have a very shady area, opt for a rex variety that will provide bright cor through foliage rather than blooms.

Overwatering

Close-up of watering a blooming begonia in a black clay pot in a sunny garden. Begonia has dense, lush foliage, heart-shaped, purple in color with a thin green edging along the edge. On long stems, there are  4-5 small flowers of bright red and pale pink collected in inflorescences. Flowers consist of 4-5 waxy petals and a yellow center. In the blurred background, there is a sunny garden.
Begonias prefer moist soil, but not soggy.

Begonias do not tolerate being in wet soil. They will simply rot. This will also cause them to lose their flowers. Test your soil by sticking your finger into it. It should feel moist but not soggy.

Brown, Crispy Leaves

Crispy brown leaves is another common problem you’ll likely encounter. It can be caused by a few different things. Once you identify the cause, it can be remedied. Let’s look at the most common reasons this happens.

Too Much Sun

Close-up of a wax begonia with white flowers and bronze leaves. Some of the leaves are crispy due to excessive sun. The flower consists of 5 rounded petals and a yellow center. The background is blurry.
Excessive full sun will cause their leaves to become crispy.

While I just went over what happens when begonias don’t get enough sun (they don’t bloom), too much sun can be equally detrimental. If your plants are looking crispy or have crispy edges, look at how much sun they are getting. Full sun conditions, 6+ hours, is usually too harsh.

There are a few exceptions, there is a series called Solenia, which can handle full sun. Or wax varieties especially those with bronze cor leaves like that of the Olympia series that will grow happily in full sun conditions.

For indoor begonias, place in a spot with bright indirect sun. Placing them in a window that receives too much direct sun can cause the leaves to get crispy. If this happens try moving your plant back from the window.

Underwatering

Close-up of a Begonia maculata plant with dry leaves due to insufficient watering against a blurred background. The leaves are large, pointed, dark green with expressive white speckles. The ends of the leaves are brown, crispy.
If you neglect to water for too long, the leaves will also become crispy.

I actually find begonias to be quite forgiving when it comes to under watering them. However, if you neglect them for too long the leaves will get crispy.

Keep the soil evenly moist, not soggy. Use a light fluffy soil so they can absorb and drain water freely. Avoid allowing your begonia to dry out completely, this will cause them to start getting crispy, as mentioned earlier.

Low Humidity

Small, black humidity and temperature sensor for the proper care of plants at home with a screen that displays the percentage of humidity and air temperature. Decorative leafy begonia in a yellow pot on a white table. The leaves are light green with dark green uniform patterns. A white flower with a yellow center blooms from under the leaves. To the left of the yellow pot is another indoor begonia plant with bright burgundy leaves. The background is blurry.
Make sure your indoor begonia has enough humidity or the leaves will become crispy.

This one is especially true for begonias grown as houseplants. The dry air in our homes can make their leaves brown and crispy. First, make sure you do not have your plant placed near an air vent. Dry air constantly blowing on your begonia will turn it crispy.

Next, try adding humidity near your plants. A tray with pebbles filled with water placed underneath your begonia will provide a bit of extra humidity. Alternatively, you can purchase a humidifier. Place it near your plants. It will boost humidity and keep your houseplants happy.

Rotting stems

Close-up of a female hand holding a neon begonia against a gray wall. Begonia has bright green heart-shaped leaves, asymmetrical on white-brown stems. Some leaves have brown spots on the surface.
Rotting stems can be caused by overwatering and lack of drainage holes.

If you find your begonia stems are rotting it is likely a watering and drainage issue. The stems are mushy and the whole plant will break off at the stem.

Stem and root rot is caused by a bacteria that thrives in damp conditions. Once your plant has stem rot, there is not much that can be done. Throw away the soil and disinfect any tools you were using on the plant.

To avoid rotting stem, make sure you are not over watering and that the container you have your begonia in has adequate drainage holes. Soil should feel moist, but not wet.

For begonias planted directly in the garden, make sure you have a bit of space between each plant for airflow. Amend the soil so it is light and fluffy. You may need to add peat moss or coconut coir before planting. Do not plant them in a low lying boggy area.

Also, when planting them in a container, plant the crown level with the rim of the pot. Don’t plant the crown below the rim of the pot, this creates a damp environment around the stem of your begonia and invites root rot bacteria.

Yellow Leaves

Close-up of a blooming red begonia with yellowing leaves in a sunny garden. The flowers are medium-sized, double, rounded petals arranged in several rows with a yellow center. The leaves are heart-shaped, pointed, green with yellowing due to excessive watering. The background is blurry.
Their leaves turn yellow due to overwatering and lack of drainage holes.

Yellow leaves is a classic sign of overwatering. If the leaves near the base are fading to yellow and falling off check the amount of water. The soil should feel moist but not wet or soggy.

Make sure you are using a nice light fluffy potting mix for potted begonias. Also, make sure your container has adequate drainage holes. Placing pebbles in the bottom is not enough.

For garden begonias, it is harder to control water because of the rain. Amending soil with peat or coconut coir will help with the absorption of excess water so the soil and plant don’t get waterlogged. Also, don’t plant them in the naturally boggy areas of your garden.

White Spots on Leaves

Top view of a potted flowering begonia infected with powdery mildew. The begonia has bright green foliage that is pointed with white powdery spots. The flowers are pink, semi-double, with a yellow center. Begonia in a pot stands on a light wooden table.
Excessive humidity is the ideal condition for the causing of powdery mildew.

Usually, white spots on the leaves mean you are dealing with powdery mildew. Powdery mildew is a fungus. It is a powdery film that coats the leaves of plants. It will stunt the growth and can eventually kill your begonias if left untreated.

Over-watering can cause mildew. The overly wet conditions is a breeding ground for powdery mildew. Make sure the soil is evenly moist but not soggy and wet. When watering also try not to spray the foliage with water.

For container begonias, I recommend bottom watering. Leave the plant in a tray of water and let it suck the water up through the drainage holes. Discard the excess water. This will ensure even watering and lessen the chance of powdery mildew.

For garden begonias, I like snaking a drip hose through the garden and watering at soil level instead of overhead sprinklers. If you are overhead watering, try and do it in the early morning as opposed to evening.

That way the water on the leaves will quickly dry in the sun as opposed to having the foliage sit wet all night. Wet foliage is a breeding ground for powdery mildew.

Spacing of plants is also a consideration. Leave space between them to allow for airflow between the plants. If you have detected mildew, you can purchase a fungicide at the garden center. Spray as directed. Then work on prevention.

If the mildew is really bad, I sometimes toss the plant and start over. Replace the potting soil with fresh new soil so as to not reinfect the new plant.

Little White Bugs

Close-up of spider mites on the stem and leaves of a plant under sunlight. A thin cobweb with many small insects is formed on a purple stem with green leaves with brown spots. The background is blurry.
Get rid of spider mites with a blast of the hose or insecticidal soap.

If you notice mottled leaves and a silky webbing on your plants with little white bugs, take a closer look. Tiny spider-like insects, spider mites, might be infesting your plants. If this is a houseplant, move it away from your other plants.

They spread like wildfire. Start by wiping or washing the leaves and stems of the plant. For outdoor plants, try a blast of the hose. Be careful using insecticidal soap. Begonias are sensitive to it. Spot test a leaf and wait 24 hours to see if the leaf wilts from the insecticidal soap.

Sudden Plant Death

On the concrete floor are 6 black, brown and white plastic pots with a dead begonia plant due to frost. The stems and leaves of the plant are sluggish, soft, drooping, not subject to recovery. The background is blurry.
Since they aren’t frost-hardy plants, a sudden frost can lead to death.

Begonias are not frost hardy. If your plants are beautiful one day and then laying limp on the ground the next, you may have had a frost in your area. Even low temperatures without frost will take its toll.

The leaves will be nipped and brown and they will slowly die. They need temperatures above 50F (10C) to thrive. Pay attention particularly to night temperatures. This is more important in the spring than fall. I find newly planted begonias are more susceptible than established ones. But once a frost hits they will die.

If you live in an area where you only encounter an occasional frost, cover your plants with a sheet or frost cloth. Don’t use tarps or plastic, they don’t protect from frost.

Stunted Growth

Close-up of a strawberry begonia growing in a brown pot, top view. The leaves are beautiful, heart-shaped, green with white veins, and thin small hairs all over the surface of the plant. Stems are red. White fertilizer granules are scattered on the moist soil.
Make sure your soil has enough nutrients by adding fertilizer, compost, worm castings, or sea soil.

Stunted growth can be a sign that your begonia is not getting enough nutrients. They are heavy feeders, especially the ones with big beautiful flowers.

For begonias grown in the garden make sure you are amending your soil prior to planting. Top dress garden beds in the fall or spring. You can use compost, aged manure, worm castings, or sea soil. No need to dig it into the soil. The nutrients will seep down over time.

For container grown begonias I start with a nice light fluffy potting soil. Then I fertilize. Outdoor containers I fertilize every two weeks in the summer months. An all-purpose 20-20-20 works great. You can also top dress containers with some worm castings.

For indoor plants, again I start with light fluffy potting mix. Then I fertilize every two weeks during the active growing season. I don’t fertilize in winter when they are dormant. A 20-20-20 works great. I tend to use a liquid fertilizer for my indoor plants.

Brown Spots

Close-up of a diseased begonia outdoors in a black oblong plastic container. Leaves are heart-shaped, pale green. Some leaves are yellow with crisp brown edges, some leaves have brown spots on the surface. A pair of bright pink flowers emerge from under the leaves.
Brown spots that show up on their leaves may be caused by foliar nematodes.

Irregular brown lesions on the leaves of your begonia is not a good sign. This could be caused by foliar nematodes. Unfortunately, there is no treatment for them. Dispose of the plant to limit spreading. Do not put it in your compost.

Make sure you rule out other possibilities before diagnosing with foliar nematodes. Read number two to rule out any other causes of crispy, brown leaves.

Leaves With Holes

Close-up of a snail on a pink begonia flower. The flower has rounded petals and a yellow center. The snail is small, has a small shell with a brown stripe. The body of the snail is translucent. The background is very blurry.
Snails and slugs feed on plant leaves, leaving holes behind them.

Begonias love moist shady gardens, so do slugs and snails. If you notice holey leaves and trails of slime, look for slugs and snails. These slimeball pests love to feast on foliage.

There are some options to control slugs and snails. You can hand-pick them. This is best done in the early morning or the early evening. It’s time-consuming but oddly satisfying.

You can sprinkle crushed eggshells or diatomaceous earth (which can be purchased at garden centers) around your begonias. The sharp shards will cut up the slugs and snails. They won’t cross them to get to the plant. This will have to be reapplied after heavy rains or tilling the soil.

The beer method works for catching slugs and snails. Fill shallow trays with beer and leave them in the garden. Empty the trays every morning or evening and refill as needed.

Slug bait also works. It is toxic to dogs, so use with caution, but it works. Sprinkle it throughout your garden. The slugs will disappear.

Plants Look Like They Were Eaten

Close-up of an illumination begonia blooming with orange flowers in a white hanging basket. The flowers are double, collected in clusters, and hanging from the red stem. The leaves are dark green and pointed. There is another hanging pot of orange begonia hanging in the blurred background.
It is recommended to hang your begonias to keep them out of reach of deer.

If the begonias in your garden just appear to be eaten. It’s probably deer. Deer love the blossoms of begonias and will eat their fleshy tubers happily. There are a few ways to deter deer.

The variety you’ve chosen will impact if deer will snack on them. Wax begonias with waxy or fuzzy leaves are generally avoided by deer (I say this, but a hungry deer will snack on almost anything).

Another great deterrent is simply keeping them out of reach. Hanging baskets of a hanging variety of begonia is a great way to enjoy those shady blooms without pesky deer.

Using sprays that will deter deer, or sprinkling blood meal around the garden will also deter them, keep in mind it will need reapplied after rain or sprinklers.

Final Thoughts

Begonias are loved by both gardeners and houseplant enthusiasts. It’s one of the few plants everyone can agree on. Keeping them healthy and happy is simple for the most part. If you run into troubles, hopefully, these 11 tips will get you back on track to growing healthy and beautiful begonias.

SHARE THIS POST
calathea leaf curl

Information

9 Reasons The Leaves on Your Calathea Plant are Curling

Leaf curl is a common problem amongst calathea plants. The key is figuring out why it's happening, and then correcting the problem. However, prevention is also the best defense with these popular houseplants. In this article, gardening expert and houseplant enthusiast Madison Moulton examines the primary reasons leaf curl could be happening to your calathea plants, and how to fix it.

A large monstera leaf from a mature plant that's grown with yellowing leaves.

Information

Does Your Monstera Have Yellow Leaves? Here’s What to Do

Does your monstera have yellow leaves, but you aren't quite sure why? There are a number of different reasons this can happen, and luckily many can be fixed fairly easily. In this article, gardening expert and houseplant enthusiast Madison Moulton walks through why this can happen, and what your next steps should be to help revive your plant.

african violet wilting

Information

7 Reasons Your African Violets Are Wilting and Dying

Are your African Violets wilting and dying unexpectedly? There are a number of different reasons that this can happen with these popular flowering houseplants. In this article, gardening expert Liessa Bowen looks at the different reasons your African Violets may be wilting, and dying early.

pilea problems

Information

11 Common Problems With Chinese Money Plants

Do you have some problems with your Chinese Money Plant and aren't quite sure what to do? Pileas are fairly low maintenance plants, but they can have occasional problems. In this article, gardening expert and houseplant enthusiast Madison Moulton walks through the most common problems you are likely to encounter with your Pilea.

peace lily brown tips

Information

11 Reasons Your Peace Lily Has Brown Tips and How to Fix it

Does your peace lily have brown tips and you aren't sure why? There are several reasons that this can happen. In this article, gardening expert and houseplant enthusiast Madison Moulton examines the most common reasons why peace lilies get brown tips, how to fix them and how to prevent it from happening in the first place!

hosta problems

Information

14 Common Problems With Hosta Plants

Curious what kind of problems hostas can carry with them once they are planted? Hostas can run into several issues, but many of them are preventable or treatable. In this article, certified master gardener Laura Elsner walks through the most common problems with hosta plants and how to prevent or fix them.