Healthy boxwood has rich green, often glossy foliage. If this discolours, there are usually pathogens or pests behind it. But not if the leaves turn orange or reddish: In this case, easy-to-resolve care mistakes are usually the cause.
Leaf discoloration is usually an indication of disease infestation
Reddish leaves on boxwood have many causes
But before you reach for the watering can and pruning shears: Some types of boxwood tend to develop brownish to reddish leaves in autumn. This is especially true for box trees in sunny locations, which prepare for the winter in this way. In the spring, the leaves will turn green again all by themselves, so you don't have to make any further efforts.
dryness
The situation is different, however, if the discoloration occurs after a longer dry period. This can be a problem for the boxwood, especially in winter, which is why you should water the plants from time to time on frost-free days. This applies above all to box trees in sunny, dry locations and to box trees cultivated in tubs.
Nutrient/nitrogen deficiencies
In addition to winter drought, a lack of nutrients often causes reddish to orange leaves. This leaf discoloration is mainly caused by a pronounced lack of nitrogen, which usually only appears during the winter months… Ensure a balanced supply of nutrients to avoid the phenomenon. In an acute case, provide the box with a fast-acting liquid fertilizer.
boxwood rust
If, on the other hand, the orange-colored leaves did not appear in winter or spring, but in autumn, an infection with the boxwood rust pathogen, Puccinia buxi, could be the cause. This is indicated by rust-red discolored spore deposits on both the upper and lower sides of the leaves. Remove infested plant parts immediately and never dispose of them in the compost but always with household waste! In the event of a severe infestation, a suitable fungicide can also be used.
tips
Brown to black leaves can also have similar causes. Some of these are harmless - such as sunburn - while others threaten the entire boxwood population.