Improper pruning timing can lead to several risks for both plants and the surrounding ecosystem. Cutting back perennials too early may disrupt their natural energy transfer to the roots, weakening their growth in the following season. Dead foliage left unpruned after frost can harbor pests like slugs and iris borers, which may damage plants in the spring. Additionally, diseased foliage, such as powdery mildew on bee balm or garden phlox, can carry over into the next growing season if not removed. However, delaying pruning until after the first frost can mitigate these risks while supporting local wildlife.