Box plants (Buxus) are a timeless choice for gardens and landscapes. Their evergreen foliage, structured form, and slow, steady growth make them perfect for hedges, borders, and topiary.
Unfortunately, in the UK, box plants are vulnerable to two major problems:
Box blight fungus
Box tree caterpillar
The good news? With the right care, both issues can be managed effectively.
Much like rose growers expect to deal with blackspot, box growers will likely encounter box blight (Cylindrocladium buxicola) at some point. This fungal disease thrives in mild, damp weather.
Strengthen plant health with a regular foliar feed (e.g. Topbuxus Health Mix). Strong plants resist disease better.
Disinfect tools before and after working on box plants.
Clip in dry weather (MayâAugust) when fungal spores are less active. Avoid damp conditions that spread spores via tools.
Treat early if blight appears with a fungicide approved for ornamental plantsÂč.
Prune out infections on mature plants and dispose of them safely. Blight does not affect roots, and new shoots will regrow.
Apply protective fungicides in spring and autumn, when infections are most likely, and before clipping.
Clear fallen leaves (do not compost). Spores can survive on leaves for up to six years.
Encourage air circulation by avoiding very tight clipping and spacing plants well.
Avoid highly susceptible varieties like Buxus sempervirens âSuffruticosaâ. Instead, try Buxus microphylla âFaulknerâ, which shows better resistance.
The box tree moth caterpillar can cause severe defoliation, feeding inside protective webbing that makes control harder.
Hand-pick isolated caterpillars, often hidden between leaves and webbing.
Prune and dispose of infested shoot tips in winter (young caterpillars overwinter there).
Use insecticides for large infestationsâensure sprays are forceful enough to penetrate silken webbing.
Biological control:
Bacillus thuringiensis var. kurstaki (a selective biological insecticide) is very effectiveÂč.
Nematodes (sold as âFruit and Vegetable Protectionâ) can reduce populations.
Organic contact pesticides can help, but require repeated use. More persistent synthetic options are also available.
Encourage wildlife such as jackdaws and bluetits, which feed on caterpillars naturally.
If youâd rather avoid the hassle of blight and caterpillars, consider these reliable substitutes:
Ilex crenata
Euonymus japonicus
Pittosporum tenuifolium âGolf Ballâ
Taxus baccata (yew)
Lonicera nitida âMaigrunâ
Osmanthus Ă burkwoodii
Lavandula angustifolia (lavender)
Berberis darwinii
Photinia âLittle Red Robinâ
Pittosporum tenuifolium âGold Starâ
All professional chemicals should:
Be applied only by a licensed user.
Always follow the label instructions.
Be tested first on a small section of the plant to avoid adverse reactions.
Be rotated between two or more fungicides to reduce resistance.
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Posted 6th Apr 2:22pm
