If you are a gardening fan, you may have already discovered that Begonias (Semperflorens Cultorum) have a reputation for being high maintenance. Therefore, if you’ve managed to grow these finicky plants to adulthood and you’re pleased with how they look, nothing is more horrifying than to discover the leaves are suddenly doing their best imitation of a potato chip.
Obviously, this is the last thing you want, since these beautiful, alluring plants out-pretty much of their competition with little effort.
With their attractive foliage, ranging significantly in shape and color, and their broad, heart-shaped leaves, there is little you could add to make them lovelier.
This is particularly true with multicolored varieties, which often look as if color was painted on in swirls of pink, silver, brown, purple, and crimson.
Begonias thrive and produce spectacular flowers in the shady conditions that are usually the kiss of death to other flowering plants.
This, in addition to their outstandingly attractive appearance, is reason enough to solve that crisping problem and maintain your begonias as long as possible.
What Makes Begonia Leaves Crispy?
Dehydration is one of the top causes of crispy begonia leaves. In most cases, begonia leaves that are dry and crinkly should be watered immediately.
Low humidity may also be a culprit, as this plant thrives in warm, humid conditions, but not in direct sunlight.
The latter is yet another reason you may discover crinkly, crispy leaves, sometimes even featuring brown spots. Don’t overlook disease either, as there are several that can cause crispy leaves.
1. Lack of Water
If you’ve noticed crisping of your begonia leaves, you should evaluate the surrounding soil to determine if it is dry. Dehydration quickly causes begonia leaves to turn crinkly, and it is imperative to water them at once if this is determined to be the problem.
As a general rule, you should water your begonias two to four times a week, but this should definitely be adjusted depending on the climate and the amount of direct sunlight to which your begonias are exposed.
In mild climates, they should thrive if you water them twice weekly, remembering to check the soil for dryness on a regular basis. In hot, dry climates, you should water them four times a week, especially during the hottest times of the year.
Begonias should not be watered daily, however, since this can easily lead to overwatering. The exception to this rule is where dragon wing and wax begonias are concerned, since, unlike other varieties, they need up to eight hours of full sun per day.
Because they are typically exposed to more sunlight, they naturally need more frequent watering, so this should not lead to crisping leaves for these varieties. Remembering their temperamental preferences is key with regard to watering all begonia types.
2. Factoring in Humidity
Begonias grow well in warm, humid temperatures, and therefore low levels of humidity may be the cause of crispy leaves.
This is particularly true for rex begonias–the most temperamental of all varieties. If dry weather is underway, or the weather in your home is humidity free, this should be remedied.
Misting, using a humidifier, or adding water to a tray of pebbles near your plants are all ways to increase humidity.
However, for a specific variety, polka dot begonia (begonia maculata) misting is not recommended. This is because it can lead to a leaf condition called powdery mildew. Once underway, it can be difficult to eliminate.
3. A Word About Heat Stress
As previously mentioned, begonias are high maintenance plants and enjoy being temperamental. This sometimes makes it difficult for you to determine what they want.
For example, although they are hot weather plants, they demand very specific conditions regarding temperature: warm, but not scorching, humid, but no soggy soil please, and sunlight, but not too much.
If this delicate balance is not achieved, begonias can become heat stressed, leading to crispy, dry leaves. The best way to avoid heat stress is to offer your begonias morning sun exposure, with dappled shade for the rest of the day.
In particularly hot climates, their exposure should be limited to two hours of full sun, and shade for the remainder of the daylight hours.
4. Overdoing (Or Under-doing) Fertilizer
Finally, crinkly begonia leaves may occur if you use fertilizer inappropriately. For example, if you over fertilize, salt can build up in the soil, which can ultimately harm the roots of the plant, leading to crisping leaves.
Similarly, if your begonias are not fertilized well, the soil will become too sandy, and lack of nutrition is often the result.
The leaves will look crinkly and brown, regardless of whether they are over or under fertilized, so it’s important to determine which one is the culprit if you believe fertilizer is the problem.
5. Could Disease be the Cause of Crispy Begonia Leaves?
Like all plants, begonias are susceptible to certain diseases.
If the issues outlined above have all been crossed off your list and you do not believe they are the source of the problem, try to evaluate your begonias for diseases or pests.
Thrips
Thrips is one of the most common pest problems for begonias.
These are tiny, slender insects with odd, asymmetrical mouthparts and fringed wings. They thrive by puncturing the leaves and consuming their contents.
Sticky traps, Neem oil, and peppermint oil are some great remedies for thrips.
Powdery Mildew
Powdery mildew is a disease that causes crisping and browning of begonia leaves. They may also curl and develop white patches.
Eventually, the leaves will die if this problem is not remedied.
Powdery mildew can be stubborn, but the best way to eliminate it is to get to the source, such as overwatering or soggy soil, and once the underlying cause is addressed, the problem eventually abates.
Anthracnose
Anthracnose is caused by fungi, and is one of the most common of all begonia diseases. In addition to the leaves becoming crispy, they may develop colored spots as well.
These can be white, brown or gray.
The best remedy is to destroy and remove any infected plants, and use a copper-based fungicide or organic solution to lightly spray the begonias for the purpose of preventing future infestations.
6. Be Careful With Rover
It’s imperative to understand that begonias are poisonous to dogs. If ingested–particularly the roots–kidney failure and other organ problems can rapidly occur.
Therefore, only consider growing begonias if you do not own a dog or if you are certain that the dog can be kept from the plants. It is also wise to keep cats away from begonias, but these plants are not typically fatal to cats.
Rather, it may simply make them vomit. However, it is always wise to err on the side of caution with all pets if you plan to grow begonias.