Answer: Lady's Mantle will grow in either full sun or part shade. I think they do best with some protection from hot afternoon sunshine. When the flowers begin to fade, cut the flowering stem down to remove it. A few more flowers will appear throughout the summer. Lady's Mantle is drought tolerant once established so too much water can cause brownish leaf edges or dried up looking leaves. I'd prune off the affected leaves to encourage branching and healthy new growth.
Unless it is dieseased, tall phlox shouldn't die out. (Mildew is a real problem with phlox, and although David's is disease resistant, if plants are overcrowded and air circulation is poor, it can develop mildew). If your phlox is overcrowded, dig and divide to keep them healthy.
Best wishes with your garden!
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