Seeing someone ruin a perfectly good evergreen by pruning it incorrectly drives me nuts. For example, a mass planting of junipers on a nearby slope was gorgeous until last summer, when the bottom row was pruned into a straight line with electric hedge clippers. Now the trimmed edge has gaps in the foliage that will never fill in. Or the time that a friend took out her frustrations on a globe arborvitae, leaving a huge hole that will be there forever.

Here’s how to prune evergreens so that they stay healthy and beautiful.

Broadleaf evergreens (like hollies, boxwoods, and cherry laurels) are easy. They have dormant buds along each stem that can eventually fill in any holes caused by pruning or other damage. Broadleaf evergreens may be pruned selectively for shape anytime through mid-summer.