We Have an Acer tree contained by the garden?
Answers: Sounds close to "Tar Spot," a fungus-caused disease which is ugly but not especially risky to the tree.
The leaves will drop off, and you enjoy to rake them up *immediately*. Otherwise, the fungus that causes the disease will convey out spores which will live in the ground during the winter and re-infect your tree subsequent summer.
You can hire someone to spray a fungicide, but it will be expensive (they have to take both sides of every leaf so spores from unsprayed leaves don't spread) and conceivably futile (if you have neighbors whose trees are infected, spores can spread from their trees.)
Take a palm leaf to a good nursery for diagnosis.
Here's a relation: http://plantclinic.cornell.edu/factsheet...
http://hgic.clemson.edu/pdf/hgic2005.pdf...
looks like it might be a fungus
Check underneath the leaves to see if within is any bugs then spray near a systemic spray there are slightly a few on the market your local garden spotlight will give you backing on this.or even B&Q.
That's called black spot. Spray beside a solution of rose clear on a dry night (not within direct sunlight) and then again contained by about 3 weeks. Pull sour any leaves that you can and burn them. Its not too serious a problem so don't panic give or take a few it, it is quite effortless to control.
Sounds like your acer trees are diseased
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