Our site is reader supported, this means we may earn a small commission from Amazon and other affiliates when you buy through links on our site.
Most of the issues you face with any plant including your box plant have to do with less-than-ideal conditions. It’s important to understand that pests and diseases don’t typically attack a plant unless it is already at a disadvantage. This might mean a plant that’s drying out because of inadequate nutrients or water that leave it’s acceptable to pest infestation or inadequate air flow and light which leave it susceptible to fungal infections.
That said, it’s important to provide your box plant with as effective a start as possible by keeping conditions ideal and checking on your plant regularly so that you can stop a problem before it escalates. Nonetheless, it’s important to be able to identify different symptoms that you might encounter with different parts of the plant.
Problems that affect the leaves
- If you notice that the colour on the leaves has faded entirely and it has burn spots on it it could simply have been scorched by the sun. Excessive sunlight can cause sunscald to your leaves. This is also more common in fresh growth so pruning later in the year can resolve this issue.
- If the foliage turns a light bronze colour or has an orange hue it could be the result of environmental stress usually if that discolouration happens right after a hot weather spell. However, this could also be symptomatic of root damage in the wintertime because of waterlogging.
- If the foliage turns yellow it can also be symptomatic of waterlogging especially if you already know that your garden has heavy clay soil. Look at improving your soil to improve drainage.
- During the winter if you notice the margins and the tips of the leaves turning yellow this is simply a result of low temperatures and it will recover some spring.
- If you have your plant in an exposed area it’s more likely to have leaf discolouration often caused by cold winds. This usually also recovers in spring when new foliage appears.
- For younger growth, the newer developments in the springtime, if there is a late frost in your area the younger growth might turn a pale brown. We only recommend pruning young plants in spring and then prune around August once they are established. This helps avoid many issues including box blight.
Learn how and when to properly prune box plants help avoid many of these problems.
In almost all of these situations, you can apply fertilizer in the springtime, clip away any discoloured areas, and this will go a long way toward rectifying the problem.
Problems that affect the roots
The roots are subject to one particular problem and that is waterlogging. If you notice damaged roots you want to remove them and trim them back after you have replanted your box plant. You will know if the roots are waterlogged when you remove the roots from the ground for an examination and you notice a black or blue colour in the cross-section, with roots that fall apart and simply fall off the plant when you try to tease them. Sometimes this issue is found too late and plants cannot be saved.
The dreaded box blight (Cylindrocladium buxicola)
The biggest problem you will face, however, is that a box blight. This is one of the more serious issues that box plants are susceptible to. Box blight is a disease that affects the leaves and the stems caused by a fungus. It happens when there isn’t enough air or light circulating through your plant which is why regular pruning and trimming is so important. Box blight won’t kill the roots but it is a serious problem that can affect the entire plant and usually, the only thing you can do is destroy affected plants.
The leaves will turn brown and then fall off resulting in large bare patches along the stem. You will see black streaks and die back especially on younger stems and you might even notice white spores of fungus on the underside of the leaves.
You always want to remove any affected areas and dispose of them properly. You should also frequently clip the foliage to provide better ventilation and regularly prune your hedges but not until later in the season once there established. If you have less severely attacked box plants you can try to remove affected parts of the plants and spray with a fungicide. Badly affected plants are best removed. It’s worth mentioning that fungicides can help suppress box blight but will not control it completely.
Always clean your pruning tools or clippers with disinfectants in between use to minimize the spread.
Recommended for treating box blight
Volutella blight (Pseudonectria buxi)
Volutella blight results in leaf spots, bare patches, and stem dieback on your box plant just like Buxus blight but luckily it’s not as bad and can be controlled more easly.
It’s caused by a fungus and can leave characteristic black streaks. Much like other plants, and other conditions, your box plant has to be affected by environmental stress or have a wound that can be infected. You can treat this by removing disease branches and any fallen leaves on the ground so that the disease doesn’t spread.
Box rust is caused by another fungus and it’s not particularly troublesome. You’ll notice that it has rusty, blister-like pustules on the leaves developing in autumn and winter. The new leaves are affected by the fungus which continues to grow as the infected spots become thicker and bigger. You should clip away any affected areas and treat it with a fungicide.
Recommended fungicides for box diseases including box blight
No matter the disease that is affecting your box plant, you should always disinfect your tools in between clipping one plant and another. When you clip away the affected leaves or stems from a single plant, always disinfect in between time to prevent the accidental spread to another plant. Some people recommend using single-use alcohol wipes for this purpose. This is not something that should happen only when you notice a disease but something you should do regularly.
Similarly, as mentioned multiple times, it is up to you to make sure that you are plants are given the proper growing conditions and that they are not stressed in any way. A stressed plant is a susceptible plant especially to things like box blight and box rust. The more care you put into maintaining proper environmental conditions, nutritional balance, watering, and pruning and trimming, the more likely you are to reduce any outbreak of these diseases.
Last update on 2021-09-14 / Affiliate links / Images from Amazon Product Advertising API