Vitex Drawing by Rene Eisenbart

BOTANICAL NAME: VITEX AGNUS-CASTUS SOUNDS LIKE: Buy decks and use fastest COMMON NAME Chaste tree TYPE: Large shrub or small deciduous tree with open, airy, spreading habit, 10 feet BASIC NEEDS: Full sun, good drainage; drought-tolerant once established WORST ENEMY: Impatience; plant leafs out Late, so don't yank it by mistake; shade BEST ADVICE: To increase hardiness, give it well-drained soil, shelter it from wind, and don't water after July; expect limbs to be cut back by prolonged cold

Deciduous shrub

The first thing you need to know about the chaste tree, Vitex agnus-castus, is that its foliage bears a striking resemblance to that of Cannabis. Growing it might be a cheap thrill for some or a source of worry for others, depending on how strongly you covet that elusive last laugh.

The second thing you might like to know is that the shrub's been highly touted for its effectiveness in regulating menstrual cycles and relieving symptoms of PMS (I recently stumbled across a book titled Vitex: The Women's Herb). It also has a positively ancient reputation as a sexual suppressant, one that Athenian women used to keep themselves chaste while in frenzied worship of the Greek goddess of harvests. According to the Roman naturalist Pliny, the celebrants "made their pallets and beds with the leaves thereof to cool the heat of lust."

And it wasn't just the ladies. Southern European monks are said to have brewed libido-busting tea from the shrub's fruit - hence its other common name, monk's pepper (talk about your condiments).

But it's the most innocent of pleasures that have led me to the chaste tree - its performance in the late-summer garden. This woody verbena relative can play a role easily as dynamic as those of Buddleia davidii (butterfly bush), Hibiscus syriacus (rose of Sharon), Campsis radicans (trumpet vine), and Caryopteris x clandonensis (bluemist shrub).

Anything but chaste in appearance, vitex has all the angles, with a multiple-stemmed symmetry enhanced by tapered, five-fingered leaves and jaunty eight-inch flower spikes of the softest lilac blue. It's a shrub that seems always in motion, what with the aerial high jinx of dive-bombing hummingbirds and silver-backed foliage that flickers in the wind. Though vitex is capable of at least ten feet if left unpruned (or better yet, limbed up like a tree), it can also be treated as a perennial and cut back to the ground each spring (like Buddleia, it flowers on new wood).

Chaste tree is a Mediterranean native and, as such, prefers life sunny and well-drained. Though it's drought tolerant once established, it will grow faster with supplemental summer water. Still, given the modesty of these cultural requirements, it's surprising the plant isn't more of a staple in the low-maintenance garden (and that its cultivars are so difficult to find). My best guess is that the chaste tree is a hard sell in spring, when it's more stick than shrub with no sign of green. Even an experienced gardener might mistake it for dead up until June, since it's predictably late to leaf out. Alas, by the time it's really cruising, most gardeners are finished buying shrubs.

But why? Late summer's a particularly good time to reassess the garden and fortify areas of complete boredom or excessive heat with bolts of cooling blue -- not to mention a hit of sentimentality. Consider vitex a flashback to more acrid-odored times, when "hooch" meant more than Turner's partner, and libidos, like fertile goddesses, ran wild.