Boxwood is a classic victim of fungal pathogens. In some cases, even the best care doesn't help and the carefully cared for tree still gets brown leaves and shoots. However, this does not necessarily mean a death sentence, as some fungi can be effectively combated with a bold cut and the right fungicide.
How do you fight fungal infections on boxwood?
To combat boxwood fungus, diseased plant parts should be generously cut out and the plant treated with field horsetail broth. If the infestation is severe, the use of chemical fungicides may be necessary.
Typical fungal infections on boxwood
There are a number of harmful fungi that exclusively or preferentially attack the boxwood. These include the following candidates:
- Cylindrocladium buxicola: also known as boxwood fungus, causes the dreaded shoot death
- Volutella buxi: causes boxwood cancer, resulting in shoot death
- Puccinia buxi: causes boxwood rust, recognizable by red-brown pustules on the upper side of the leaves
Characteristic features of every fungal disease are leaves and shoots turning brownish and drying out, with only yellowish to brownish spots often appearing on the foliage in the initial stages. In most cases, not the entire boxwood is affected, but only some of the branches and shoots. Depending on the pathogen, white to reddish-brown spore deposits can be found on the underside of the leaves in advanced infestation.
Prevent fungal infection effectively – This is what you have to do
Since almost all fungal diseases occur as a result of humid and warm weather, you should take precautionary measures when the weather is bad:
- Always water boxwood trees from below, never over the leaves!
- If possible, leaves should not be permanently moist.
- Never cut in rain or damp weather!
- Then the risk of infection is highest in otherwise he althy plants.
- Keep boxwoods moist, but not wet.
- Soil that is too moist and waterlogging inevitably lead to root rot.
Since weakened plants are also preferentially infected, you can strengthen your boxwoods through optimal location conditions and species-appropriate care. Above all, pay attention to a balanced supply of water and fertilizer - in addition to a lack of nutrients, over-fertilization can also have serious consequences. Furthermore, an airy, sunny location is ideal, and by adhering to the recommended planting distance you can do a lot to keep your bush he althy.
Fighting fungal infestation effectively – this is how it works
However, once the box is infected with a fungus, the only thing that usually helps is scissors. Cut out the diseased parts of the plant generously; even severe pruning will not harm the box. Because of its slow growth, it takes a long time to regain its original size and shape. Fertilize the plant to stimulate new growth, and you can also first treat it with home remedies against the fungi. A home-made horsetail broth has proven to be effective. If the measures mentioned don't help, the only option left is to use chemical fungicides - which should be carefully considered in the home garden due to their side effects! – or deforestation.
Tip
If a white to grayish, wipeable coating can be seen on the upper sides of the leaves, it is probably powdery mildew. In contrast to other fungal diseases, this occurs in bright sunshine and warmth, which is why it is also known as a “fair weather fungus”. You can get this infection under control if you treat the affected boxwood trees with a mixture of fresh whole milk and water (ratio 1:10).
