Boxwood diseases on the rise
The persistent boxwood shoot death caused by the fungus Cylindrocladium buxicola and the very difficult to control boxwood moth, whose caterpillars devour entire stands within a very short time, are particularly problematic. The latter is particularly tricky because the infestation is often noticed too late. The caterpillars begin their feeding activity inside the bush and slowly work their way out from there. If there are already hundreds of caterpillars cavorting on the book, only drastic measures will help. Both diseases have only been known for a few years; they were brought in through imports from other parts of the world. Nevertheless, they are a massive threat to the European book and the centuries-old garden culture associated with it.
also read
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- Boxwood dies - how can you still save it?
- Fertilizing boxwood with coffee grounds - useful or not?
Appropriate rescue measures
Even gardening experts were at a loss until a few years ago, but today we know a lot more about the harmful organisms mentioned - especially about how an infestation can be combated or even prevented. For both diseases it is best to use these remedies:
- Do not prune the box between April and September as usual.
- Instead, grab scissors on a frost-free and rain-free day between January and March.
- From the beginning of April, dust the box with fine algae lime.
- Algae lime is also not without problems for other reasons.
- However, it is a real miracle weapon in the event of an acute or threatened infestation.
- Consistently keep the soil pH between 7 and 8.
- Ensure a balanced supply of water and nutrients.
As a preventive measure, you should never plant box trees too densely, but rather leave a little more space between the individual plants. You should also choose less sensitive varieties: The border varieties 'Blauer Heinz' and 'Suffruticosa' in particular are often severely affected, while others (such as 'Faulkner' or 'Herrenhausen') are rare.
When is it better to replace the boxwood?
If the infestation occurs before June, even a bare box tree can often be saved. It becomes more difficult, however, when the disease, with its drastic effects, occurs later in the year. The earlier the infestation and control take place, the more time the book has to recover and to sprout again. However, the probability that a bush that is bare or severely pruned in autumn will recover and sprout again by spring is low.
Tips
Brown leaves often indicate a fungal disease, but sometimes it is just a sunburn.
