Box blight— does your hedging look like this?
“Box” or Buxus sempervirens is one of New Zealand’s most popular forms of low hedging and has been treasured for many years both here and in Europe for centuries at historic gardens such as those at Versailles and the National Trust in Britain. Unfortunately our beloved box has been affected by a box blight which was first seen in New Zealand in themid 1990s. It has spread through the North Island and yes . . . you guessed, we have it here in Tauranga.
The blight is actually spread by water splash, thus the reason we have been seeing it so much lately . . . toomuch rain!
The symptoms of box blight include: ■ Leaves turn brown and fall, leading to bare patches ■ Black streaks and dieback on young stems ■ In wet conditions thewhite spore mass of the fungus may be seen on the under sides of infected leaves (place the leaves in a plastic bag with a tissue for a few days to check)
So what do we do if box blight has struck your beloved hedge or topiary?
Firstly prevention is better than cure, so managing a pending outbreak is important. Take care as to where you would plant Buxus sempervirens (English box) hedge. There are alternative box varieties which are resistant to blight such as Buxus microphylla (Japanese box).
Grow in an open and well ventilated spot. Prune the hedge on dry days only and to a convex rather than flat top. Ensure that tools and clothing are cleaned before and after pruning with a garden disinfectant ormild bleach. Clean away all clippings and remove from the property.
If you have infected wood prune this out and it is wise to cut out more than you think you need to, no matterwhat time of the year.
Start a regular spray programme and continue this right throughout the year. Make sure that the spray gets right up and into the plant and spray the ground around too.
We recommend regularly spraying with combined Grosafe Buxus Blight Fighter & Grosafe EnSpray 99 Oil. Then alternate with a combination using Grosafe Free Flo Copper + Grosafe EnSpray 99 oil (throughout the year)and add Grosafe Biopower Seaweed Flake (through the growing season). These products are all Biogrow certified.
In addition Yates Fungus fighter, which is a systemic fungicide could be used every third spray as an extra precaution. Be patient and you will be pleased with the result.
If the infection is really bad you may need to consider removing the plants completely alongwith any leaf litter and starting againwith Japanese box. Sad but true.
Box blight has spread through the North Island including Tauranga.