As summer approaches, so does a bounty of blue and purple-flowering summer perennials and annuals, such as salvia, scabiosa and scaevola. Plants that flower in the purple color range attract butterflies to the garden, making for a lively show. But purple is not just for herbaceous perennials and annuals: One of our favorite blooming trees is the chaste tree, or Vitex agnus-castus, which sports stunning large spikes of purple blooms in summer.
Vitex is a beautiful, small deciduous tree or, more precisely, a large multi-trunked shrub. Related to lemon verbena and vervain, members of the plant family Verbenaceae, Vitex is originally from the Mediterranean and western Asia. This origin makes the tree very well adapted to growing in our Texas climate. Often mistaken for butterfly bush, this beauty grows to about 15-feet tall and just as wide, with an open sprawling growth habit. Blooms appear on new wood in late spring and early summer in a cloud of purple. In addition to attracting butterflies, Vitex also draws visits from pollinating bees and hummingbirds. The flowers are followed by a small fleshy fruit with seeds that can sometimes be used as a pepper-like seasoning. There are several color variations available, such as ‘Shoal Creek’, a lovely lilac color; and ‘Montrose Purple’, deep color with longer spikes. If you love the look of lilacs, you’ll love this Texas-tough alternative.
Vitex is easy to grow in sunny locations and in many kinds of soil, as long as the area does not collect too much excess moisture. Plants will even tolerate salt drift, so they can be grown in coastal areas of the state. This is not a shrub to be hedged, boxed or pruned too heavily. Selective pruning can be done to maintain a smaller size, but its natural open growth habit requires that you give it space to sprawl. Avoid planting it too close to a driveway or street, resulting in the sides of the shrub being pruned too heavily. Because blooms develop on new wood, any necessary pruning should be done in fall or late winter. Once established, plants are very low-maintenance and drought tolerant.
The next time you’re looking for a small ornamental tree to plant in your garden, consider adding a beautiful chaste tree…. The butterflies will thank you!