<em>Vitex agnus-castus</em>, chaste tree: planting, growing, pruning

Description and botany

Vitex agnus-castus, literally “chasteberry”, also called Gattilier, chaste tree or monk’s pepper, belongs to family Verbenaceae. This aromatic shrub or bush is native to poor, well-drained soils and dunes of the Mediterranean basin, especially Greece and Italy, and to Asia Minor.

The genus includes more than 200 species, of which Vitex agnus-castus is the most widespread in our temperate zones.

With fairly rapid growth, Vitex forms a rounded, bushy shrub with a flexible, spreading habit, sometimes a little untidy. Mature, it will measure, depending on cultivar, about 1.50 to 3 metres, rarely exceeding 4 metres in any direction, and is ideal for creating flowering, country-style hedges. Vitex agnus-castus develops a very deep root system and can display century-long longevity.

Beige-grey bark flakes with age, forming scaly fissures on the trunk.

The deciduous, deeply divided foliage varies noticeably from one cultivar to another. The stems are quadrangular, cracked and very flexible, developing opposite, palmate leaves with a long petiole, composed of 5 to 7 lanceolate leaflets with smooth margins, the two basal ones shorter. Their fan-like shape evokes the cannabis leaf. The Vitex agnus-castus ‘Latifolia’ or large-leaved Gattilier is distinguished from the type by broader, shorter foliage.

The leaves are satiny with a velvety whitish underside and a prominent chartreuse-green midrib. They appear in spring in shades of light green, grey-green to dark green, sometimes nicely purplish, as in cultivar ‘Flip Side’®. Gattilier leaves are aromatic and give off an intense peppery scent when crushed, as does the whole plant, hence its nickname “pepper tree”.

Vitex agnus-castus — botanical illustration by PJ Redouté

In summer, dense spikes of scented flowers cover this elegant foliage. From July to October, when fewer plants are in flower in the garden, the branches of Gattilier bear beautiful axillary panicles in a range of colours reaching 10 to 20 cm in length. Resembling buddleia blooms, this flowering occurs on current-year shoots. The flower buds, tightly packed together, open progressively into small flowers of 7 to 8 mm, tubular and almost two-lipped with five unequal lobes and prominent stamens. They are pubescent on the reverse. These whorls come in various shades of blue ( ‘Blue Puffball’), violet, pink and pure white (Vitex agnus-castus ‘Albus’).

Highly melliferous, these flowers with a peppery, balsamic fragrance are much visited by pollinating insects and irresistibly attract butterflies and bees.

In autumn, clusters of round, edible and fragrant berries 4 to 5 mm in diameter, resembling bright red peppercorns follow the flowers and persist through winter. They have a spicy flavour and can be used as a pepper substitute.

Perfectly hardy down to -15°C, Vitex agnus-castus or Gattilier adapts to all our climates and is very easy to grow in very sunny situations in ordinary, well-drained soil, even poor, stony and calcareous. Undemanding about soil type, it is an all-purpose bush that also tolerates sea spray and adapts to saline and sandy soils.

It finds its place in natural gardens, dry gardens, seaside or urban gardens. It excels when planted alone, in shrub borders or clumps, in flowering hedges or even on a terrace or balcony, grown in a large container for more compact varieties.

Vitex has long been associated with chastity. In the Middle Ages, some monks consumed its berries for their anaphrodisiac properties to resist carnal temptations.

Several colours of Vitex: ‘Delta Blues’, ‘Latifolia’ and ‘Alba’

In herbal medicine, the berries and leaves of Gattilier are used to relieve hormonal pain in women and to regulate the menstrual cycle. Its peppery seeds can be used as a condiment. Formerly, Vitex stems were used, like wicker, to make strong ties and trellises.

Main species and varieties

Most popular

Our favourites

Vitex agnus-castus Delta Blues - Chaste Tree

A very recent variety with a particularly elegant habit and a sustained vivid blue flowering. Its modest growth allows it to fit into small gardens, in an informal hedge or as a clump.

• Flowering time August to October
• Height at maturity 2,75 m

See the product sheet

Vitex agnus-castus Albus - Chaste Tree

It flowers all summer, right up to the doorstep of autumn, producing masses of pure white flowers. Used in large and small gardens in country hedges or as a solitary specimen.

• Flowering time August to November
• Height at maturity 4 m

See the product sheet

Vitex agnus-castus Blue Puffball - Chaste Tree

This brand-new chaste tree is the smallest in the genus! Tuck it into mixed borders or into a large pot on the terrace.

• Flowering time August to October
• Height at maturity 1,10 m

See the product sheet

Vitex agnus-castus Flip Side - Chaste Tree

This new American variety stands out for the striking colouring of its foliage, beautifully purple-tinged, a habit more compact and elegant than the type. Plant in an informal hedge or as a clump!

• Flowering time August to October
• Height at maturity 2,50 m

See the product sheet

Vitex agnus-castus f. latifolia - Chaste Tree

This variety is more vigorous than the classic variety and is distinguished by broader, shorter foliage and larger flowers. It establishes well everywhere, in flowering hedges as in shrub borders.

• Flowering time August to October
• Height at maturity 2,75 m

See the product sheet

Planting Vitex

Where to plant?

The Vitex or chaste tree agnus-castus is one of the flowering bushes easiest to grow. To flower well, it must be planted in full sun, in a warm spot sheltered from cold, drying winds that could damage its foliage. If it shows a good resistance to cold down to at least -15°C in well-drained soil, it still fears very severe frosts, but will regrow from the stump in spring. In cold regions, plant it against a sunny wall.

It tolerates sea spray and will cope well with summer drought once established. With an exemplary undemanding nature, it thrives in any soil that is not too wet, salty, sandy, poor, or even calcareous, provided it is well drained, as this bush of arid lands fears excess moisture.

With its versatile nature, Vitex finds its place in all natural gardens, dry, seaside or urban gardens, forming attractive focal points. It can be used throughout the garden, as a specimen, in a bush border or grouped in informal hedgerows. Some compact varieties such as Vitex agnus-castus ‘Blue Puffball’ are particularly suited to small spaces and to container growing and can be used in small perennial borders or at the front of a bush border.

When to plant?

Plant Vitex preferably in spring, from March to May, in cold regions once all risk of frost has passed to encourage a good restart. Elsewhere, planting in autumn, from September to October to encourage rooting before winter is also possible.

How to plant?

In open ground

Depending on variety, allow a density of 1 bush per m2. For a hedge, allow a distance of 1 to 3 m between each Vitex or other bush. When planting in open ground, improve drainage if needed using coarse gravel mixed half and half with your garden soil. Water regularly during the first summer.

• Dig a hole twice as wide as the rootball and loosen the soil well
• At the bottom of the hole, place if needed a thick bed of gravel or clay balls to ensure drainage
• Place the bush centred in the planting hole so that the rootball is level with the soil surface
• Backfill with garden soil
• Firm the soil around the base of the bush and water

In a pot

Compact Vitex (such as the variety Blue Puffball) are perfectly suited to container growing and make a statement on the terrace where they will release their peppery scent in summer.

• Choose a container large enough, at least 60 cm high so the bush can develop well
• Spread a draining layer of clay pebbles or pumice
• Plant your vitex in a mix of leaf mould and garden soil
• Place the pot in full sun
• Water fairly regularly during the first summer, allowing the compost to dry out between waterings
• Repot every two years into a larger container

Maintenance, pruning and care of Vitex

Hardy, drought-resistant, Vitex is a robust bush that requires little maintenance: no fertiliser, little watering. It is the ideal companion for low-maintenance dry gardens!

Water young bushes during first summer to help root establishment and during first 2 or 3 years in case of prolonged heat. Afterwards, let nature take its course, and water only during long dry spells; it will make do with rainwater.

In a pot, allow soil to dry between waterings and, in regions with wet winters, bring pots under cover.

In coldest regions, mulch plant base from autumn to protect from severe frosts.

Vitex, when properly established, has no significant pests; moreover, its peppery scent repels nuisances!

When and how to prune?

Pruning Vitex is not obligatory, but it helps maintain compact, bushy habit: carry out this operation at end of winter or early spring. Like all summer-flowering bushes, Vitex flowers on current season’s wood; very short pruning will encourage growth of new branches and upcoming flowering will not be threatened but rather stimulated! No worries, it tolerates this type of pruning well!

1. In March, before growth resumes, cut flowering shoots back by three quarters with pruning shear, leaving only 2 or 3 eyes or buds
2. Remove dead wood and crossing or errant branches
3. Open up centre of branches to improve air circulation

And follow our advice for pruning summer-flowering bushes properly

Multiplication

Taking cuttings of chaste tree

Propagation of Vitex can be done in August on semi-ripe or semi-woody shoots (i.e., those that transform from soft wood to hard wood). Expect 2 to 3 years for first flowering. Sowing is possible with fresh seeds in autumn but more erratic and slow.

• Take non-flowering current-year shoots 15 to 20 cm long
• Remove lower leaves and keep only two pairs of terminal leaves
• Cut them in half
• Plant cuttings in buckets filled with potting compost and sand
• Overwinter them frost-free under cold frame
• Keep substrate moist
• Plant out cuttings in open ground from following spring

Combining chaste tree with other plants in the garden

With its fragrant flowering combining freshness and simplicity and with its moderate size, the Vitex agnus-castus is suitable for large and small gardens, as a specimen, at the back of a perennial border or grouped in informal hedges, or even in a container. It pairs easily with all kinds of plants in a natural garden or a coastal garden because it tolerates sea spray well.

It works wonders as a flowering hedge when mixed with all types of flowering bushes such as Ceanothus (California lilac), weigelias, a smoke tree, altheas, lavateras and other bushes such as buddleias.

A lovely planting idea: Vitex agnus-castus ‘Flip Side’ as centrepiece, accompanied by Cistus ‘Alan Fradd’, Salvia officinalis ‘Purpurascens’, Santolina chamaecyparissus, Foeniculum ‘Bronze’, Verbascum thapsus and Calamintha nepeta. Add a few clumps of Stipa gigantea and it will be perfect!

Its bushy silhouette helps fill out a natural shrub-and-perennial border, adding plenty of charm. Position it in the background, for example alongside a Lagerstroemia.

In the foreground of a shrub border, modest-sized chaste trees pair well with oleanders, dwarf buddleias, or with Tamarix.

In the back of a mixed sunny perennial border, it lightens the whole and blends easily with salvias, Alcea rosea, Achillea millefolium, summer asters, Nepetas, lupins, Oriental poppies, Echinacea, creating lush, generous displays.

Larger specimens form magnificent backdrops for old garden or English roses.

It ranks among the garden’s finest blues; create a blue-themed border by pairing it with butterfly bushes such as ‘Adonis Blue’ or ‘Blue Chip’, and with blue-flowering perennials like Delphiniums, Knautia arvensis, Echinops, Perovskia, a Salvia nemorosa or Verbena bonariensis, or a Lupinus ‘The Governor’.

With its blue, pink or white flowering it features in romantic scenes punctuated by tufts of lavenders and grasses such as Miscanthus, together with clematis, campanulas, Thalictrum. In blue/yellow combinations, set it against snowberries, yellow daylilies, drought-tolerant euphorbias, St John’s wort and shrubby potentillas.

Compact varieties are well suited to container culture in containers mixed with hardy geraniums, phlox or dianthus or lavenders.