The mini heatwave we had earlier this month has been playing havoc with my box trimming.
The weather on two days was too hot and sunny to even contemplate clipping box.
In extreme sunny weather and with temperatures in the thirties (Celsius), the risk of sun scorch is too high. And the risk to the topiarist is even higher!
No joke. I attempted clipping some box in a walled garden that are in shade all day. But the temperature was still high and made worse by the heat radiating off the the walls.
I felt ok during the day but come evening when I returned home, I felt awful. Must have been a mild case of heat stroke. Reminded me how careful you need to be when working in hot weather.
Thankfully the box I had clipped was fine because they were in the shade for the most of the day. I have found it’s usually the hot sun and not the heat that causes the Buxus leaves to bleach white.
Sun scorch on Buxus
However careful you are about not clipping in sunshine, sun scorch is always a risk. Have a look at these box balls below.
These Buxus were clipped and looked fine until scorching in the hot sunshine two weeks later.
The box balls are planted in an area that gets full sun for more than eight hours a day so scorching is always a possibility- even if they haven’t been clipped.
Extra watering can help, which is why these Buxus are regularly irrigated by a leaky hose that is wrapped around their bases.
How long does sun scorch last?
This bleaching of the top leaves doesn’t look great but thankfully doesn’t last long.
The box balls in the photo below also suffered with mild scorching on the top leaves. But the bleached white patches soon grew out to be replaced with this lovely, lime green, healthy new growth.
If you do have to clip Buxus in sunny weather then cover immediately afterwards with a sheet or similar, and leave in place for as long as possible.
Soaking the sheet in water can hold it place longer, especially in breezy conditions.
Covering Buxus like this may reduce the risk of bleaching but is not guaranteed.