Question: How can I encourage my herbs to grow? Should I be pruning them? -David W.
Answer: If your herb plants are healthy and thriving, and you want to encourage them to grow larger, there are two easy ways to go about it. (If your plants aren’t healthy, adjust their care requirements like sun, water, and soil needs first to get your herbs in good health before enacting either of these plants. A bit of stress goes along with both options, which won’t hurt healthy herbs, but the stress could be detrimental to plants that are already struggling.)
First, moving your herb plant to a larger container will give it room to develop a more extensive root system under the surface of the soil. After it’s built more roots and is taking in higher levels of water and nutrients, the plant will start to spread out so it can fill the larger container. Remember that containers for growing herbs, like other plants, should always come equipped with drainage holes so your plant doesn’t get too soggy and risk falling prey to mildew, root rot, or fungal disease.
When you change the size of a plant’s container, don’t forget that you’ll likely need to change its watering schedule, too. Plants in larger containers don’t need to be watered as often as those in small pots because the extra room allows the soil to retain moisture longer.
Pruning your herb plants back will also cause them to grow larger and bushier, although unlike with transplanting, gardeners aren’t free to prune their plants year-round. However, if your recommended pruning schedule’s timing lines up with your desire to encourage more growth for your herbs, you’re in luck. If you skip pruning altogether, as your herb plants mature, they’ll either go to seed after flowering, produce fewer leaves and turn leggy and spindly, or stop producing foliage and become entirely woody (for those with wood stems). Pruning is a requirement if you want to get the longest life and the maximum harvest out of your herb plants. Even baby herb plants that are still quite small should be pruned at the appropriate time of year as long as the plant is well established and growing strong. All types of herbs need to be pruned, whether you’re growing them indoors or outdoors, in containers or in the soil outside. Pruning actually stimulates new growth, so the plants will come back even bigger and better than before, and the plant’s shape will be bushier and more compact after pruning.
All herbs should be pruned during their peak growing season, when they’re producing new growth at the fastest rate. This maintenance is called light pruning. You can cut away up to a third of the plant’s bulk the pruning session resulting in long-term damage. Leave the large leaves at the plant’s base intact. They’re most important for photosynthesis because their larger surface area allows them to take in significantly more sunshine than the rest of the plant’s foliage.
Make your cuts at the node where leaves connect to the plant’s stem. If you cut using the “tipping” technique, removing just the top one or two inches of your herb plant’s stem, the stem will branch into two wherever it was cut, resulting in thicker, denser foliage. Parsley and chives require a different approach. Cut these herbs back until only an inch of growth remains above the soil. After pruning, parsley and chives will start to generate new foliage in about a week.
Because herbs tend to be smaller and more delicate than other plant varieties, you don’t have to use pruning shears and instead can use your hands or a pair of kitchen scissors. Just make sure that whatever you use is clean and sterile. If you prune with your hands, pinch straight through the stem in a single motion; do not tear or rip your plants. Tearing or ripping can cause damage and disease.
Throughout the season, you should also pinch off flowering structures or trim them back as they develop—before the blossoms appear. Once your plant has started growing flowers, the leaves will lose their taste. If you don’t remove the flowers, your herbs will stop producing leaves, instead focusing on flowers and seeds. Eight weeks before the first frost of winter is expected in your region, stop pruning until the next peak season rolls around.
At the beginning of the year, when your herbs have just begun to produce new growth, evergreens and perennials need a hard pruning. In hard pruning, you should strive to remove a quarter to a third of each branch on the plant as well as cutting away all dead branches and foliage. Unlike annual herbs, which need more frequent pruning throughout their growing season, perennials and evergreens should have a single hard pruning session once per year. The only exception to standard pruning rules are lavender varieties. Lavender needs to be pruned drastically in late summer or early fall. When you’re pruning lavender, cut the plant back so that just three or four inches of green growth remain on top of its woody stems.