Camellias are very bright inhabitants of my garden. They are unpretentious and a pure pleasure to watch. Sometimes, however, they can be a bit troublesome and I will tell you about one such trouble in this article.
Sooty mold is the main cause of the blackening of camellia leaves. Also, mites, direct sun, and overwatering can cause camellia leaves to turn black.
Read on to learn more about these problems. I will also tell you what to do to correct each of these problems.
Sooty mold is a disease of fungal origin. However, it all starts with insects, oddly enough. Pests such as aphids or scale parasitize on the leaves and branches of the camellia. As a result, they release a sticky substance that falls on the leaves below.
Then a fungus comes into play that parasitizes on these secretions. This whole process can take anywhere from a few weeks to a few months.
At first, faint blurry black spots appear on the leaves. The more secretions fall on the leaves, the more black they become. By midseason, all of the lower leaves can turn completely black.
How to fix this?
The first thing you need to do is find the insects. They can be on the upper branches as well as on the lower part of the leaves at the top of the plant. It is also possible that the pests will be on the tree underneath where the camellia is growing.
If you find aphids, spray them with an aqueous solution of horticultural oil. In most cases two sprays are enough.
If you find a scale, spray the leaves with insecticide. Repeat the spraying several times during the season and again the following spring. This pest is difficult to get out so you will have to work hard.
Hose the blackened leaves down with water to clean them up a bit. After a few days, spray them with a multi-purpose fungicide.
A second cause of camellia leaf blackening can be spider mites. In general, these are very small creatures that cannot be seen without a magnifying glass. They are very similar to small bugs but they are not insects.
There are several species of spider mites that parasitize the camellia. They penetrate the tissues of the leaves and petioles and feed on the sap of the plant. Around their habitat, they create a very small cobweb that protects them from moisture which they do not like.
When the pests become abundant they draw off a lot of sap and the leaves turn greyish brown with black areas in the center. Also, the lower part of the leaves and leaf petioles can have faint cobwebs on them.
How to fix this?
The first thing you need to do is to wash the mites off with a hose. They don’t like water and this will make life very difficult for them.
Next, spray the leaves with horticultural oil. You can buy a concentrate and dilute it in water or use a ready-to-use product. Repeat the spraying in a few weeks to kill the mites that hatched after the first spraying.
If the problem persists, buy a product called acaricide (miticide). It is specially made for the control of these pests. Use as indicated on the label. Usually, you need 2-3 sprays per season to get rid of the mites completely.
Camellias are those plants that need some shade. In general, they can grow in full sun most of the year, but in the hot summer the sun can burn the leaves. This is especially common if the camellia is growing against the south wall of the house and receives not only direct sun all day but also reflected heat from the wall.
Symptoms of sunburn are large dark areas on the leaves. Their color can vary from dark brown to black. After a while, the damaged leaves will completely shrivel up and fall off.
How to fix this?
To avoid sunburn, plant your camellia so that it only gets direct sun for part of the day. For example, place it on the east or west side of the house.
If sunburn occurs, water the camellia with a few gallons of water once. Then install shade over it for the summer. You can use a garden umbrella or shade netting to do this.
Next spring, transplant the camellia to a place with less direct sun. Or plant a taller tree in front of it to get some shade in the middle of the day.
Very often the leaves turn black because of root problems. The fact is that damaged roots are not able to provide the plant with water and this primarily affects the leaves.
In most cases, the cause of a damaged root system is overwatering or stagnant water in the soil. As a result, the roots suffer from lack of air and begin to rot.
If root rot occurs in warm and sunny weather, the leaves will shrivel up and turn brown. But if the weather is wet and cloudy, the leaves can stay green for a while, but there will be large black areas on them.
How to fix this?
The first thing to do is to stop watering the camellia too often. Allow the soil to dry 2 inches between waterings.
To avoid camellia root rot, plant it away from water sources (ponds, roof water, etc.). Avoid placing it in heavy, poorly drained soil.
If root problems persist, transplant the camellia to a less moist location. Do this only in early spring and use organic matter to improve the native soil.
Unfortunately, there are a number of diseases that can severely damage camellia. They all have different origins, some fungal, others bacterial, but the most dangerous are viral diseases.
Some of these diseases destroy the cells of the camellia foliage. As a result, black dots or spots appear on the leaves. Sometimes half a leaf or even a whole leaf can turn black.
How to fix this?
If black spots appear on the leaves, spray them with a multi-purpose fungicide or copper fungicide. Repeat the spraying after a few weeks.
Also, stop watering the camellia frequently and try not to water over the leaves. Make sure there is good air exchange around it.
If the blackening was caused by a fungal or bacterial disease, in most cases the above recommendations will solve the problem. However, if it is caused by a virus, there is nothing you can do.
Will a camellia recover from blackened leaves?
In most cases, the camellia will recover from blackened leaves. Those leaves that have turned black will no longer turn green, but the new ones will have a natural look. Of course, this will only happen if you solve the problem that caused the camellia to suffer.
If the camellia has been affected by Sooty mold, the recovery will be quite quick. The main thing is to kill the pests that caused it, and next year you won’t even notice that there is something wrong with your camellia. The same applies to sun damage, mite damage, and fungal diseases.
In the case of root rot, the recovery process may take 1-2 years. But if you do as I recommend above, it’s going to be fine.