How to Grow a Stunning Chaste Tree (Vitex) for a Thriving Garden

Chaste tree is a beautiful, summer-blooming shrub that attracts a variety of pollinators. It is a fast-growing plant that produces dense clusters of upright flowers up to 12 inches long from late spring through fall. They are usually blue-violet but can be purple, pink, or white. Both the flowers and leaves have a distinctive spicy scent.

Chaste tree is native to Europe and parts of Asia and is often grown as a large, multi-stemmed shrub but can be pruned to a single trunk, reaching 20 to 30 feet tall. The smaller size of many cultivars is best for small gardens. It grows best in warm climates. In cooler areas (zones 5 and 6) it is often grown as a perennial and cut back to the ground in winter. In spring, it quickly produces new shoots that reach 3 to 5 feet tall, making for a spectacular summer flower display.

Where to Plant a Chaste Tree?

This heat-loving plant needs full sun to grow best. It prefers slightly acidic to neutral, well-drained soil. Since it is as wide as it is tall, be sure to leave plenty of space. The chaste tree makes a stunning specimen lawn, or several can be planted in a row along a driveway or property line. It is also useful as a background plant in a sunny, mixed border garden.

When and How to Plant Chaste Tree?

Plant chaste tree in the spring after the danger of frost has passed. The plants are slow to sprout leaves and grow, but once they do, they grow quickly. Water the plant well in its pot before gently lifting it. Loosen the roots with a claw tool or your fingers. Spraying the root ball with a stream of water will help loosen the feeder roots further and give them a chance to spread out.

Dig a hole twice as deep and wide as the root ball. If your soil is heavy clay, add some compost to loosen it. Set your plant so that it sits at the same depth it was growing in the container (or slightly higher) and then fill the hole with soil. Press the soil down as you do this to eliminate air pockets. When the hole is half full and again when the hole is completely full.

Chaste Tree Care Tips

Once established, chaste trees are virtually carefree. They have few pest and disease problems. Depending on your vision, annual pruning may be your biggest maintenance task.

Light

Place your chaste tree in full sun, where it receives at least 6 hours of direct sunlight each day. Although it will grow in less sun, it will almost never flower.

Soil and Water

Well-drained soil is important for healthy trees. In soil that is constantly wet, the roots will rot. If your soil is heavy clay, amend it with compost or choose a different location. These plants are moderately salt tolerant.

Water your chaste tree regularly until it is established and growing, after which it usually does not need any more water. It tolerates dry soil.

Temperature and Humidity

This is a heat-loving plant that also tolerates high humidity. It can survive winter temperatures as low as 9 degrees Fahrenheit below zero. However, in colder areas, it can suffer from winter death, so it is often grown as a perennial that grows entirely from its roots each year.

Fertilizer

Avoid over-fertilizing this plant as it will produce excess leaves at the expense of flowers. A small amount of slow-release fertilizer below the drip line every other spring should be sufficient.

Pruning

It is best to harvest in large quantities in late winter. To prune the shrub as a multi-stemmed shrub, select four or five main stems and clean out the center, removing most of the branching interiors, and cut them back to a single main branch. To shorten a branch, cut it back to a bud or side branch. If you want to shape the shrub and make room for the plants beneath, cut the lower branches back to the main branch.

To prune a single-stemmed tree, select the main stem when the plant is young, and remove the side branches to the desired height before allowing the upper branches to grow. Prune the crown of the tree as you would a multi-stemmed shrub, by opening up the center and removing the bud growth to the central branches.

Instead, cut the entire plant back to the ground and let it grow back in the spring. To encourage continued flowering and prevent self-pollination, remove faded flowers.

Planting and Replanting

Small, compact chaste tree varieties are suitable for container planting. Just make sure the container is large enough to accommodate the root ball and has large drainage holes. Equally important is excellent drainage of the potting mix.

It is necessary to repot the chaste tree into a larger pot with fresh potting soil every 2 to 3 years when the shrub outgrows its container.

Problems and Pests

Chaste trees are rarely pests. Aphids, scale insects, and whiteflies are occasionally seen, but these can usually be controlled with a strong spray of water or insecticidal soap.

There are few diseases that bother this shrub unless it is growing in a damp location where root rot can occur. Avoid such locations, or improve soil drainage.

How to Propagate Chaste Trees

Chaste trees root easily from softwood cuttings taken in late spring or early summer. Take a four- to six-inch-long cutting, then remove the flower buds and lower leaves. Dip the ends in rooting hormone, then place the cuttings in containers filled with moist sand or perlite, and cover with a plastic tent.

Keep the growing medium moist but not wet. After about 6 weeks, roots should form. If more than one cutting has rooted, transplant the extra cuttings into separate containers.

The chaste tree reseeds freely, so you will find volunteer plants near your plant. Dig them up and plant them in a suitable location or container.

To start a chaste tree from seed, collect and extract seeds from ripe fruit in the fall. Plant them in a container filled with well-drained soil, water them, and leave them outside over the winter. After the seeds germinate, transplant the plants to a larger container in the spring.

Types of Chaste Trees

Selections vary in size and flower color. Newer, more compact varieties are better suited to smaller landscapes.

Shoal Creek

With a dense, multi-stemmed growth habit, this cultivar grows 10 to 15 feet tall and up to 12 feet wide and has large, violet-blue flowers.

Alba

This cultivar grows 10 to 15 feet tall and up to 20 feet wide, producing an abundance of white flowers in late spring or summer.

Rock Steady

'Rock Steady' is more compact than the other cultivars, reaching 4 to 12 feet tall and only 4 to 5 feet wide. It produces lavender flowers nonstop over a very long season.

Pink Puffball

This cultivar grows to 4 to 8 feet tall and bears medium-sized pink flowers.

Blue Puffball

Another smaller selection, 'Blue Puffball', has sky-blue flowers on upright plants that reach 4 feet tall and wide.

Frequently Asked Questions

Why is my chaste tree producing so few flowers?

The poor blooming is caused by a lack of sunlight. Chaste trees need at least 6 hours of direct sunlight per day. You may need to prune nearby trees or move your holly to a more sunny location. Another problem could be over-fertilization, which encourages plant growth at the expense of flower production.

What is the difference between chaste tree and butterfly bush?

Both are deciduous shrubs that produce colorful clusters of flowers that attract butterflies and other pollinators, but chaste tree and butterfly bush are not closely related. Chaste tree is in the mint family, while the (not very pleasant) butterfly bush is in the fig family.

Why is it called the chaste tree?

Historically, the aromatic leaves were recommended as an aphrodisiac to suppress sexual desire. Although this is not recognized as a viable use, it led to the name chaste tree.