For Midsummer Bloom, Consider the Chastetree (Vitex)

Closeup of Vitex, Photo/Karen Lawrence

By Dr. Bob Gilbert

It is difficult to find a tree or shrub that has showy blooms in the summer. There are not many. Buddleia or Butterfly bush comes to mind first. But, I try to not to consider it anymore because it is so invasive. Our neighbors have it and it requires constant attention pulling up the seedlings. A far better choice is Vitex negundo(vi-teks nee-gundo), Chastetree, Five Leafed Chaste Tree, Chasteberry, Monk’s Pepper or Cloister Pepper. Most commonly this is called simply Vitex. There are some other species of Vitex occasionally available that are not as hardy as negundo.

For this shrub you need room. It grows with multi-stems and can reach 20-25 feet tall and wide. You often see it in highway median plantings. When it reaches its ultimate height, the branches tend to arch downward. It can easily be kept smaller by pruning as it blooms on new growth. It makes a wonderful background plant as its bloom spikes are at the end of the branches producing a light blue haze. We especially enjoyed it just at twilight when the light becomes pink or gloaming. The blue blooms absorbed the pink light and became deep, a richer blue — even purple.

Vitex is native to Asia and India. It provides a good source for honey when blooming. It can be grown in full sun or high shade and is not very particular about soil or moisture. It grows quickly. There are no other color varieties, although I was once given a pale pink variety that was not very pretty. In retrospect it was likely a species of some sort as it did not last very long. All Vitex produce small hard seeds that look like pepper corns. It is reported that the seeds germinate easily, making it somewhat weedy. I did not have this trouble with the three mature specimens we grew in Kennesaw.

Vitex planted in 1989 provides a backdrop for the Perennial Garden, Photo/Bob Gilbert

There is a cut-leaf variety, “Heterophylla,” whose leaves reportedly look like marijuana, whatever that is. This variety’s leaves are so attractive that in March the plant is often pruned back close to the ground. The resultant new shoots are grown just for the foliage and only get four to five feet in height. This technique is called pollarding. Note the white arrow on a pollarded Catalpa tree also pruned just for its foliage.

All in all, horticulturally Vitex is a great shrub. But it is also known for its many medicinal properties. It gets its common name Chaste Tree as Athenian women would put leaves in their beds to keep themselves pure. Teas made from the berries are a tonic for both male and female reproductive systems. Also in ancient times it was used as an anti-aphrodisiac, thus the name Monk’s pepper. In modern times extracts are used in the management of PMS and other things.

Vitex is a derivative from Latin, meaning “to weave,” as its branches can be used in basketry. Vitex has interesting history, grows well here, and produces blooms when most other plants have finished. You should be able to find it at most Nursery Centers. As Michael Dirr says, “it makes attractive summer flowering.”

Dr. Bob Gilbert’s articles are being reprinted with the permission of the Franklin Press in Franklin, North Carolina.