Pruning herbs keeps them growing well. Removing flowers, leaves and parts of stems, 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 remedied before the entire herb is affected.
Almost all herbs will benefit from regular cutting. Pruning back keeps them thick and lush, provides plenty of tasty herbs for cooking and seasoning, and keeps the garden in shape.
Before Getting Started
With some types of herbs pruning is as easy as pinching with your fingers to remove unwanted flower buds or smaller stems. For the best results, remember to pinch cleanly through stems instead of crushing them, When pinching flower buds, be sure to remove the entire bud. Anything left behind can stunt growth.
Consider using sharp garden snips. Snips work better for herbs with woody stems like rosemary, sage and lavender. They allow for the more precise cuts needed to train these herbs into a full, desirable form.
It is not often that herb gardeners need to haul out the bypass pruners, but mature woody plants may require a tougher tool. Use rose pruning shears or bypass pruners when you need a clean, neat cut through a thick woody stem. Avoid tearing or stripping the stem. This is unsightly and can lead to disease.
When to Prune Herbs
All herbs, both tender stemmed and woody should be pruned when dry. After morning dew has evaporated and before it arrives again in the evening, is the best time to work with your herbs. Since pruning equates to harvesting in the herb garden, when to cut back will depend on what part of the herb you intend to use; flower, leaf, or stem.
Pruning for Flowers
Popular herbs like lavender and chamomile are grown for flowers and buds. You can begin regular harvesting of the flowers mid-season as soon as they open or when the buds appear on lavender plants. Limit your harvest to new green growth and take no more than 1/3 of the plant. This will increase branching and encourage more flowering.
Pruning for Leaves and Stems
Tender annual herbs like basil and mints will benefit from regular cutting back and harvesting as soon as the plant has several sets of leaves. Regular pruning promotes branching which helps to shape the plant and improve the harvest.
The same holds true for plants with woody stems, however, since many woody herbs are perennials with a slower growth rate, it is generally not necessary to prune these herbs as often.
Spring or Fall Pruning
Some annual herbs, like dill, cilantro and chamomile, reseed readily. If you desire an ongoing annual harvest, leave the seed heads in the garden at the end of the season. Other annuals can be cut to ground level or removed entirely.
Some other herbs like chives spread through seed and underground rhizomes and can quickly become invasive. Flower heads should be removed at the end of the season to prevent unwanted spread.
Perennial woodies can benefit from a hard pruning either late in the fall or in early spring. Cutting back up to two-thirds of these plants in the late fall can help redirect energy into the roots, which is a better option for young plants. It is best to wait until after several hard frosts since pruning too early will encourage new growth.A hard pruning in spring, as soon as you see new growth at the base, can stimulate growth on your more mature woody herbs.
Equipment / Tools
- Garden snips
- Harvest basket or trug
- Gloves (optional)
Pinch Back Leafy Herbs
When annual leafy herbs have developed three to four sets of leaves begin by pinching back the stems. Using your thumb and index finger grasp the stem about 1/4 inch above a leaf and give it a decisive pinch. Avoid twisting or pulling as you pinch. This can cause damage by stripping the stem. As the growing season continues, pinch out any flowers or flower buds that form.
Trim Woody Herbs
To shape and harvest woody herbs during the growing season, use snips or bypass pruners to make cuts either for shaping, harvesting or both.
Use the snips or pruners to make a slight diagonal cut across each stem above a leaf node, careful not to damage the node, removing up to two-thirds of the old growth. Avoid cutting into the older woody part of the plant, taking off only new green growth.
Do the hard pruning of these herbs in late fall/early winter or early spring.
Maintain Garden Health
Pruning helps prevent disease. Overgrown, crowded plants can become vulnerable to mildew growth. Keeping them trimmed so the air can flow freely around the stems and leaves creates a much healthier growing environment.
If left to grow, bloom, and die back on their own schedule, your herbs can become top-heavy and unsightly with bare or leggy stems. Pruning will keep everything in check, healthy, and growing on your schedule.