Black spot

Symptoms

Leaves are marked with purple or brownish-black spots, then turn yellow and fall. Smaller marks sometimes also blotch the stems. Plants can be weakened by regular attacks.

Find it on: shrubs, roses

Time to act: spring, summer

Problem categories

Overview

Leaves and sometimes stems are marked by dark blotches caused by a fungus. The spores overwinter on fallen leaves, stem lesions and bud scales, and reinfect the plant the next spring when there's a flush of new foliage. If these leaves are then infected, they too eventually turn yellow and drop. If not dealt with, the plant will weaken.

Rose black spot is very similar and can be dealt with in the same way.

Solution

Leaves are marked with purple or brownish-black spots, then turn yellow and fall. Smaller marks sometimes also blotch the stems. Plants can be weakened by regular attacks.

Organic

Fallen, affected leaves must be promptly destroyed, along with any stems showing signs of infection. The best way to avoid the problem - which thrives in warm, wet conditions - is to lay a thick mulch around the plant. This helps lock moisture in the ground, and stops rain splashing the spores from the soil on to new growth.

Chemical

Spray with a fungicide containing myclobutanil. Begin spraying each fortnight from early spring, just as the new foliage emerges, as a preventative measure.

Discuss this problem

Talkback: Black spot

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ajc.lb@btinternet.com 24/11/2011 at 15:27

I have a bay tree 3ft tall in a big urn shapped pot abot 2ft, it has always been lovely but this winter the leaves have got a lot of black on them - I have sprayed with anti fungal, but still no improvement, I don't want to lose it any suggestions please

dannysgirl 24/11/2011 at 15:28

Can you tell me please how to reduce the size of my large hydrangea, or the best way to cut it back. it's really beautiful, but has grown to big for my small front garden.

Thank you, Audrey

joannah 24/11/2011 at 15:28

Hi, a friend was putting newly cut grass in a thick layer around her rose plants. I feel that I have read somewhere that this is not a good idea, but I cant remember why!

Coulstons 24/11/2011 at 15:29

I have a dwarf pear tree in a pot in our garden. We have had the tree for about three years now. The tree has had flowers on it in the spring. But we have not had any pears on the tree yet!

Are we doing something wrong? Maybe you can advice us what to do.

lozzi 15/04/2012 at 10:56

my 15 year old Bay tree's leaves have turned brown, ( so have the ones in the local garden centre) is there a reason for this, what can i do and will it return to its beautiful former green ?

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