Answer: If all of the plants in your yard are affected with black spots, you need to do some serious pruning to open things up to sunshine and better air circulation! Black spots are caused by a fungus that is both airborne and waterborne. Because the spores need free moisture to germinate, they're more of a problem in high rainfall areas than in areas with low rainfall. Try not to sprinkle the leaves of your plants when you water, and make a daily pilgrimage out into the garden to inspect for diseased leaves. Promptly remove any leaves that develop black spots, to keep them from infecting other leaves. Once you've pinched, picked, pruned, and otherwise removed infected plant parts, the problem should diminish.
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