Prune at the Right Time
The tidy gardener in all of us wants to cut back our bushes and our trees so that they look nice. If you cut off the leaves spring flowers, like daffodils or irises, you'll be depleting their bulbs of the starch they need for next year's display. Same goes for bushes like lilac, roses or forsythia: Trim them in late summer and you could be chopping off the flower buds—which means no blooms the following season. Pruning larger trees in August could spur new growth, which would be vulnerable to cold weather.
The right way: Don't touch the leaves of spring-bloomers until they've totally faded. Trim back a flowering bush or tree right after it blooms, before it starts to form next year's flower buds.
If you've goofed: "Well, it's not the end of the world," Chace says. "Let them recover. Healthy plants are fairly forgiving." But it may be a season or two before you get the flowers or foliage you'd hoped for.