Cherry Laurel with powdery mildew and shothole

[Mila2015]

Hello,

I need your wisdom and advise. We live in London and have a mature Cherry Laurel hedge in front of our house, currently at 8ft tall. For the past year or two it is unfortunately suffering badly from powdery mildew and shothole .

We haven't done much about it as we read there isn't much you can do to cure it. We don't have a gardener and we usually trim the hedge once a year in late spring when the new leafs become too much. Unfortunately this leaves us with the old, damaged leafs for the summer.

A gardening company is doing some work currently in houses near us and they noticed our sick hedge and offered to hard trim it, removing the damaged leafs ( most of them now ). My question is this: is now a good time for hard trimming of Cherry Laurel hedge? When is the best time to do it and try to improve the overall health and minimize the powdery mildew effect and the shothole?

Any advise will be much appreciated.

Mila

[David E. Ross]

In the early spring while it is still dormant and out of leaf, spray it with a mixture of dormant oil and copper sulfate, with a little liquid soap in the mix as a wetting agent. Repeat just before the flower buds open.

No, I do not know if dormant oil or copper sulfate are available in the UK. In the US, I mix half of what I need of each (e.g., 2 quarts of each). Then I combine the two batches (e.g., to make a gallon) and add the soap. I also use this on my roses and grape vines, but I spray them only once, while they are dormant.

[Jeff Layman]

Avoid heavy trimming (see RHS link below). This is important as the current unseasonal and extremely high temperatures in London will stress the plant even more.

In the UK, cherry laurel (Prunus laurocerasus) is evergreen. Is something else called "cherry laurel" in the US?

spray it

Recommendations for treatment can be found here under "Control":

The only copper product approved for use in the UK is copper oxychloride (as Bayer Fruit & Vegetable Disease Control), and that is only for use on food crops. Use one of the "conazoles" or myclobutanil as recommended instead.

[Mila2015]

Thank you David and Jeff,

Do I then wait for the early spring for a hard trim? I need to somewhat trim it now as it is growing quite tall.

[Jeff Layman]

You can tidy it up a bit now, but no extreme pruning. Next spring take a third of it off, a third the next year, and the final third the year after that.

More details at

opposite the photo "Cherry laurels in bloom".