Why Prune Herbs?
Pruning herbs keeps them growing well. By pruning, or cutting off leaves and parts of stems, it signals the plant to continue in the growth stage. This translates to a more controlled shape for the garden, and more harvest for you! Regular pruning also alerts you to disease and insect problems that may start small and could possibly be removed before the entire herb is affected.
Prune Leafy Herbs
Some herbs, like basil and cilantro, are grown specifically for their delicious leaves. This means that left unpruned, your plant will grow, blossom and start to die back. With leafy herbs, pinch or cut them back to the leaf nodule to encourage a bush habit. This ensures plenty of new leaves for future harvests.
Later in the season, even the best kept leafy herbs will begin to lose energy and go to seed. When this happens, no amount of pruning will keep it from dying back. I plant a few herbs to grow as attractive specimens in locations that are visible from the road, then have my working beds, where I harvest (and prune) regularly, for harvest. These pruned plants are also wonderful replacements in the more visible gardens when needed.
Pruning Woody Herbs
Some herbs, like rosemary, sage, and thyme, will become woody with age. These herbs should be trimmed back to keep them from being all woody stem (which does not grow any leaf). A true pruning, not just a pinch of the leaves you are harvesting, is best done in the early spring, as soon as you see new growth starting.
It is best not to prune too late in the season. This would encourage new growth instead of the plant's energy being saved for overwintering.
Pruning is as easy as pinching with your fingers, to using snips or shears for heavier work. As a rule, when pruning leaves and flowers, a simple pinch of the fingers is adequate. Remember to pinch cleanly through the stem of the leaf, instead of crushing it, for the best results.
Use sharp garden snips if you prefer. They can help prune more exact locations on a bushy plant, and some gardeners simply prefer them.
It is not often that herb gardeners need to haul out the actual garden shears, but it does happen. Use rose pruning shears and stronger garden shears when you need a clean, neat cut through a woody stem. Avoid tearing or ripping off a stem of the plant if possible. This is unsightly and can lead to disease.
Pruning For Garden Health
Let's face it; pruning is HARD to do! Of course, it isn't hard physically, but it is so difficult to cut back our lovely herbs, even if it is the best for them. Cutting or pruning back keeps our herbs thick and lush looking, provides plenty of tasty herbs for cooking and seasoning, and keeps our gardens in shape.
Pruning also helps prevent disease. When herbs become overgrown, they can become the perfect place for mildew growth. Keeping your plants trimmed,so the air can flow freely around the plants is much healthier for them.
Overgrown herbs become top heavy and unruly. If left to grow, bloom and die back on their own schedule, your herbs can easily reseed and take over a garden. Pruning will keep everything in check, healthy, and growing on your schedule.