Trimming Basil Leaves: Tips For Cutting Back Basil Plants

Basil (Ocimum basilicum) is a member of the mint family, known for outstanding aromas. Basil is no exception, and it's one of the most popular of the tender herbs grown in the garden. With proper care including pruning, basil can provide the grower with an unlimited supply of sweet leaves until the fall. Knowing how to prune basil is an important part of maintaining this herb, and one that will encourage new vigorous growth. Not sure how to cut basil? Read on to learn how.

About Basil

The genus Ocimum contains 64 species of aromatic herbs native to subtropical to tropical climes worldwide. Most basil varieties are grown for their culinary uses, but some are grown more for their ornamental traits, for pest control, or to cure medicinal ailments.

Basil’s flavor comes from a blend of several compounds making it taste like an agreeable combination of citrus, mint, licorice and spice.

Sweet basil has smooth, green, aromatic leaves. The plant grows about 2 feet tall by 15 inches across (61 x 38 cm) and produces small, white blooms atop stalks.

How to Grow Basil

A tender annual, basil requires well-draining, fertile soil in an area that gets full sun 6-8 hours per day. Basil can be grown from seed and started either 6 weeks prior to the last frost in your area or directly into the garden after all danger of frost has passed and soil temperatures have warmed to at least 60 F (16 C).

Plant seeds ¼ inch (6 mm) deep in well-draining, fertile soil in a spot that gets full sun. When the seedlings have their first two true leaves, thin to 10-12 inches (25-30 cm) apart. Basil also thrives as a container plant.

Basil is intolerant of drought. Water the plants when the soil is dry down about 1-2 inches (2.5-5 cm) into the soil. Water in the morning if possible to discourage fungal disease.

Basil Varieties

Native to Southern Asia and the islands of the South Pacific, basil is grown for its tender, flavorful and aromatic leaves. The most common type of basil grown is sweet basil, but other varieties include purple basil, citrus basil, and Thai basil with its spicy licorice flavor.

Of the varieties of sweet basil, ‘Genovese’ is the most popular, and is the type used in pesto sauce. Other sweet basil varieties include large leaves ‘Napoletano’ and ‘Italian Large Leaf’ and small leaf bush varieties such as ‘Green Globe’ and ‘Spicy Globe’.

Why Prune Basil Plants?

So what is the purpose behind pruning basil? Is it to make it bushy? Yes, like many other plants, pruning this herb encourages growth which also makes the plant bushier but that isn’t the only reason.

Basil should also be pruned before it flowers. If allowed to flower and seed, the plant becomes woody and the flavorful leaves bitter. If you are growing a basil variety for ornamental purposes, then go ahead and leave the blooms, which can be quite attractive.

When to Prune Basil

You may prune basil at any point through the growing season and hopefully if you’re growing it to add to food, you are doing this a lot. If possible, harvest basil leaves in the morning when their essential oils are at their peak and the leaves have the most flavor.

How to Trim a Basil Plant

Basil leaves are quite delicate. Barely bruising the leaf releases the aroma of the essential oils, which quickly begin to dissipate. Therefore, pruning basil leaves with care is a necessity.

It's possible to break off new basil growth with your fingers, but to ensure a clean cut and keep the plant healthy, you should always use a sharp implement like pruning shears, herb snips, or just regular scissors.

As soon as the seedlings have their first 6 true leaves, prune or pinch to just above the second set. Each time a branch gets 6-8 leaves, it’s time to pinch the basil back again.

Continue to harvest young leaves as needed, or harvest entire stems by cutting just above a pair of leaves. Within a week, you should see new growth pushing forth from the cut site.

The more often you prune the basil plant, the bushier and leafier it becomes.

Should You Pinch Back Basil Flowers?

As soon as basil flowers become evident, pinch them off so the energy in the plant stays diverted to foliage growth. If the basil plant is growing vertically, pinch the leaves from the top to encourage lateral growth. Use the pinched leaves or dry them, so there’s no waste. Basil grows quickly, so even if you don’t want to use the leaves right away (gasp!), keep trimming back the plant when it gets large and bushy.

To harvest a full basil plant, cut the herb back about ¼ inch (6 mm) above a node, 3 inches (8 cm) from the base of the plant. Leave a few inches (8 cm) of leaves on the plant after pruning. You can be quite aggressive when pruning basil like this since, as already mentioned, they are rapid growers. Even after a major cutting back, there will be new branches ready for pruning again in a few weeks.

What to Do with Basil Cuttings

Use the fresh basil immediately or store for a couple of days in a glass of water at room temperature.

If you find you have more fresh basil than you can use or give away, you can dry basil by hanging branches upside down in a well aerated room for a week. The dried leaves are then stripped from the stem and stored in an air-tight container.

Basil can also be chopped into small pieces and frozen in an ice cube tray with a little water, or processed into pesto sauce and refrigerated or frozen.

Pinching or cutting back basil plants regularly encourages full, bushy plants. There is no mystery or exact science to cutting back basil plants. Trim a basil plant every two to three weeks and pinch off the flower buds as soon as you see them. Trust me, the plant loves this and it will only encourage more vigorous growth while providing you with plenty of fresh basil leaves to stretch those culinary wings.