A couple of the box balls at a property where I often work are not looking good. The Buxus was planted in April- not by me I should add.
Box blight is my first concern, especially with browning of leaves like this. But no tell-tale black streaks are on the stems- an indication of Cylindrocladium buxicola (box blight).
Unusually this Buxus has a patch of healthy new growth on one side. Gives me a clue to look at the roots and I soon see a reason for the dieback.
The box ball has been planted on an angle with one side of the rootball raised out of the planting hole. Buxus roots are very fine and can dry out easily. This is why I always advise mulching around the base regularly.
The exposed roots on this Buxus have dried out, resulting in one side of the plant not absorbing enough nutrients and moisture to sustain leaf growth and causing dieback. The area of the rootball in contact with the soil has put on new roots, which in turn has delivered enough moisture and nutrients to encourage the small patch of new, healthy leaf growth.
Replanting maybe a possible solution for this box ball. But that is no easy task. So in this instance I am going to mulch around the base of the ball and hope the Buxus will recover.
Regular watering can help during Summer. Little and often is best to avoid the roots sitting in damp soil. Using leaky hose is ideal. This needs to be wrapped around the top of the whole rootball- not like in the photo above.
I did spray the Buxus with a fungicide, more as a precaution than anything else. Sick and stressed Buxus are more prone to fungus infections, in particular Volutella blight (Pseudonectria buxi).
I haven’t cut away any of the brown areas as hopefully there is still life in the stems. The leaves will most likely fall off and I will be careful to clear these up- again to avoid risk of fungus infections. If the Buxus does manage to put on new root growth then with luck I will start to see some new leaf growth in the Spring. Check back next year for an update .