Vitex Chaste Tree Care: 5 Types of Vitex Chaste Trees

A vitex chaste tree (scientific name Vitex agnus-castus)—also called the chasteberry, monk’s pepper, or Texas lilac—is a hardy, fast-growing flowering shrub that produces palm-like leaves and bloom spikes of light purple, white, or blue flowers in mid-summer. In home landscaping, it’s popular to prune vitex as a dense shrub or as a small tree, with some cultivars growing up to twenty-five feet tall.

The vitex chaste tree is native to the temperate climate of the Mediterranean and southern Europe. While it is deciduous and dies back during winters in USDA Hardiness Zones 5 and 6, it remains green year-round in warmer climates. In the southern United States, especially Texas, the vitex plant can grow so aggressively that it can escape landscaping and become an invasive plant. Before planting a chaste tree, you may want to check with your local garden center regarding vitex’s local growth habits.

Many cultivars of vitex are available at garden stores, which usually group them by their size and flower colors. Here are a few of the most common vitex chaste trees:

1. 1. ‘Alba’: This cultivar grows up to fifteen feet tall and features white flower spikes.
2. 2. ‘Blue Diddley’: A smaller cultivar, this plant grows up to six feet tall and has blue blooms.
3. 3. ‘Blue Puffball’: One of the smallest cultivars, this vitex chaste tree grows up to four feet tall and bears blue flowers.
4. 4. ‘Montrose Purple’: With vibrant purple flowers, this tree is one of the largest cultivars, capable of growing up to twenty-five feet tall.
5. 5. ‘Shoal Creek’: This cultivar grows up to fifteen feet tall and features blue-purple flowers.

Vitex chaste trees are cold-hardy and drought-tolerant flowering trees that need minimal care outside of pruning. Here are considerations for caring for vitex plants:

1. 1. Choose the right planting site. Vitex thrives best in a spot with full sun and loose, well-draining soil.
2. 2. Keep an eye out for pests. Vitex trees aren’t major targets for pests or disease, but keep an eye out for the usual offenders—thrips, aphids, and whiteflies—and control them early with sharp jets of water or a natural insecticide like neem oil. If your vitex tree looks diseased or yellowed, it’s likely a case of root rot from overly soggy soil. Some vitex trees might experience leaf spot. If you see diseased leaves, prune them away.
3. 3. Overwinter. If you live in USDA Hardiness Zones 5–6, your vitex tree will die back in the winter and regrow every spring as a perennial. To overwinter your plant, cut the trunk down to ground level and mulch around the base to insulate the roots from the cold.
4. 4. Prune regularly. Especially in temperate climates, it’s key to keep your vitex chaste tree’s growth rate in check. The plant can grow up to seven feet in a single growing season and can quickly become a sprawling giant. Vitex can handle heavy pruning, and some gardeners prune the tree monthly to keep it in the desired shape. At the very least, prune the tree yearly once the cold sets in.
5. 5. Water sparingly. Vitex trees prefer soil on the drier side and are very drought-tolerant. You might find you only need to water vitex trees when they are young—mature trees can live entirely off of rainwater and residual water in the soil. Nearly any growing problem you might have with a vitex tree is a result of too much water in the soil.

The simplest way to propagate a vitex tree is by taking cuttings.

1. 1. Trim off a tip of softwood branch. Choose a “new wood” branch that is soft, green new growth—hard enough that it can snap under pressure but soft enough that it still bends. Trim this branch off of the mother plant using a pair of sharp, clean garden shears.
2. 2. Remove the leaves. Tear away the lower leaves of the trimming so there are at least three inches of bare stem at the base.
3. 3. Add the cutting to water or soil. Place the bottom inch or two of the cutting in either a vase of clean water or in rooting hormone and then directly into soil.
4. 4. Wait for roots to form. Keep the cutting in bright, indirect light, sheltered from direct sun or inclement weather. Eventually, the cutting will develop small, thin roots. This can take anywhere from a few weeks to up to two months.
5. 5. Transplant the cutting. If you water-propagated your cutting, transplant it once the cutting has roots at least two inches long. If you soil-propagated your cutting, allow it to grow in the soil for several months before you harden off the vitex and transplant it into your garden. The best time to plant new shrubs is in early spring, late spring, or early summer, to give them a long growing season before the winter.

Grow your own garden with Ron Finley, the self-described "Gangster Gardener." Get the MasterClass Annual Membership and learn how to cultivate fresh herbs and vegetables, keep your house plants alive, and use compost to make your community—and the world—a better place.