Chaste tree

Sun

Full sun; choose a warm, sheltered position in cooler climates.

Water

Moderate while establishing; low once established, with occasional deep watering during prolonged drought.

Soil

Well-drained sandy, loamy or gravelly soil; tolerates alkaline soil and relatively poor ground. Avoid waterlogged sites.

Height

10-20 ft (3-6 m)

Spread

10-20 ft (3-6 m)

Flowers

Summer to early autumn; upright spikes of fragrant violet-blue to lavender flowers.

Foliage

Opposite, hand-shaped leaves with usually five to seven narrow leaflets; grey-green and aromatic when crushed.

Growth

Fast in warm climates; slower where summers are cool.

Care needed

Low

• Pollinators
• Deer resistant
• Drought tolerant
• Heat tolerant
• Wildlife
• Low allergen
• Fragrant

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1.8 ft (0.54 m)

2. After 1 year

   4 ft (1.3 m)

3. After 2 years

   7 ft (2.1 m)

4. After 3 years

   10 ft (2.9 m)

5. After 5 years

   15 ft (4.5 m)

   full size

About 5 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Invasive in

the US

In the garden

Spreads vigorously: plan to contain it.

Growth rate

Moderate

• Water deeply during dry spells through the first growing season, allowing the soil surface to dry between waterings.
• Once established, water only during prolonged drought rather than keeping the soil constantly moist.
• Apply 2-3 in (5-8 cm) of mulch over the root area, keeping it clear of the stems.
• Avoid rich feeding; use a light spring feed only if growth is weak on poor soil.
• Remove seedlings promptly where self-seeding is unwanted.

Pruning. Prune in late winter or early spring, removing dead wood and shortening last year's growth to a healthy framework; flowers form on new growth. Where winter kills the stems, wait until buds show, then cut back to living wood or close to ground level.

Late winter

In mild regions, remove dead or crossing branches and prune to maintain a shrub or small-tree framework.

Spring

In cold regions, wait for buds to reveal surviving wood before removing winter-killed stems.

Spring

Plant after severe frost risk has passed and refresh mulch without covering the stem bases.

Summer

Water newly planted specimens deeply during dry weather.

Late summer

If practical, remove fading flower spikes before seeds mature to reduce self-seeding.

Autumn

Pull unwanted seedlings and avoid hard pruning before winter.

• Use as a loose, multi-stemmed focal point in a sunny gravel garden with lavender and ornamental grasses.
• Place behind lower perennials to provide summer flower colour above the border.
• Train as a small tree beside a terrace where there is room for its broad canopy.
• Include in a sunny pollinator border with salvias, coneflowers and yarrow.

Garden styles it suits: Mediterranean, Dry gravel garden, Pollinator garden, Desert / xeriscape, Cottage garden and Southern.

Plant it with: Lavender, Russian sage, Catmint, Purple coneflower, Yarrow and Switchgrass.

Wildlife: Flowers attract bees, butterflies and other nectar-feeding insects. Its branching canopy provides shelter for small birds.

• Winter dieback: choose a sheltered site near its cold limit and remove dead stems in spring once new growth is visible.
• Poor flowering: provide full sun and summer warmth, and avoid heavy nitrogen feeding.
• Root rot in wet soil: improve drainage or replant on higher ground; do not keep the root zone constantly wet.
• Leaf spot in humid conditions: remove fallen affected leaves, improve airflow and avoid overhead watering.

Not generally known to be toxic to cats, dogs or horses, although species-specific safety information is limited. No part is generally regarded as highly poisonous to people, but the fruits are medicinally active and can affect hormones or interact with medicines; do not use them as a home remedy, particularly during pregnancy or breastfeeding. Eating plant material may cause stomach upset.

Where it spreads. Can self-seed freely in warm climates and is listed as invasive in Texas. It has also escaped cultivation in parts of the southeastern United States; check local invasive-plant guidance before planting.

• Chinese chaste tree (Vitex negundo)

  Usually has three to five leaflets with more clearly toothed edges; chaste tree usually has five to seven narrower, mostly smooth-edged leaflets.

• Butterfly bush (Buddleja davidii)

  Has similar purple flower clusters but simple, elongated leaves rather than hand-shaped leaves divided into separate leaflets.

The names chaste tree and agnus-castus reflect the historical belief that the plant reduced sexual desire.

Propagation. Take softwood cuttings in late spring or early summer, or semi-ripe cuttings later in summer. Seed can also be used, but seedlings may differ from the parent; use cuttings to preserve a named variety.

Accepted botanical name

Vitex agnus-castus

In the US and Canada

Introduced in the lower 48 states, Puerto Rico and US Virgin Islands.

Native range

Afghanistan, Albania, Algeria, Baleares, Bulgaria, Corse, Cyprus, East Aegean Is., Egypt, France, Greece and Gulf States.

Measured

Soil pH 7 to 7.5. Average height 300 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.