Chaste tree
Vitex agnus-castus · Lamiaceae Popular
A large shrub or small, multi-stemmed tree with aromatic, grey-green, fingered leaves and long spikes of lavender-blue flowers in the heat of summer, loved by bees and butterflies.
- Size
- 11½ ft tall, 11½ ft wide
- Zones
- 6 to 9
- Light
- Full sun
- Flowers
- Early July to early September
- Pets
- No toxicity recorded
- Job in a bed
- Anchor
A bed built around chaste tree
The planner designed this bed around chaste tree when this page was made: a 30 × 14 ft (9.1 × 4.3 m) cottage garden in zone 6, full sun. It chose the other plants from the 715 that suit those conditions and its dry soil, and says below why chaste tree stands where it does.
The plants
- 1 Chaste tree × 1, lavender
- 2 Cheddar pinks 'Firewitch' × 33, pink
- 3 Heath aster 'Snow Flurry' × 3, white
- 4 Dwarf Alberta spruce × 1, green leaves
- 5 Switchgrass 'Prairie Sky' × 4, tan
- 6 Stiff goldenrod × 14, yellow
- 7 Little bluestem × 3, blue-green leaves
- 8 Chives × 33, purple
- 9 Yellow coneflower × 20, yellow
- 10 Creeping phlox × 3, pink
- 11 English lavender 'Hidcote' × 3, purple
- 12 Cheddar pinks 'Bath's Pink' × 14, pink
- 13 Lemon thyme × 19, pink
- 14 Persian fritillary × 7, purple
- 15 Hyacinth × 5, blue
- 16 Triteleia 'Queen Fabiola' × 31, blue
Why this plant
- The only lavender.
Why here
- Anchors a back corner. At 11½ ft it is the tallest plant here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to stiff goldenrod (4 ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- One plant, alone. A shrub is seen as an object, and needs clear ground around it.
Why now
- In flower for 10 weeks. From early July to early September.
- Fills a gap. For one of those weeks nothing else on the plan is in flower.
Planned as a cottage garden: 106 of the 151 plants (70%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. Cool colours (lavender, pink, purple and blue) with yellow as the warm note, and white and tan to calm things between them. Among the neighbours here are six pairs of recognised partners, such as Cheddar pinks 'Firewitch' and English lavender 'Hidcote'.
The planner's own design check: 13 Excellent, 3 Good, 1 Satisfactory. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where chaste tree goes in a border
At 11½ ft it belongs at the back of a bed. In the planner's ten height classes it is super tall (over 6½ ft).
Its job: anchor. A shrub that gives the bed permanent structure. Planted singly, as soon as the front edge is laid; everything else is arranged around it.
It flowers in the hottest weeks, when little else does. In colder zones it dies back in winter and is grown as a large perennial, cut down each spring.
- Summer flowers for hot climates
- A substitute for lilac in the South
- Bees and butterflies
What to plant with chaste tree
Plants recorded as good partners for it, and what each pairing does:
- Russian sage: in flower together for nine weeks, from mid July; low enough (4 ft) to stand in front of it; happy in the same dry soil.
- Autumn sage: in flower together for 10 weeks, from early July; a low mound at the foot of its spires; low enough (2½ ft) to stand in front of it.
- Pink muhly grass: takes over when it finishes, flowering from mid September; a low mound at the foot of its spires; low enough (3 ft) to stand in front of it.
Questions about chaste tree
Does chaste tree need sun or shade?
Chaste tree grows in full sun (6 or more hours of direct sun a day).
It wants dry, sharply drained soil, of average fertility, and little watering once settled. Once settled in, it stands drought.
What zones does chaste tree grow in?
USDA zones 6 to 9. It is hardy to zone 6, which means it survives winter nights down to about 0 °F (−18 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does chaste tree flower in my zone?
In zone 5 it flowers early July to early September. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 6 | Early July to early September |
|---|---|
| Zone 7 | Late June to early September |
| Zone 8 | Late June to early September |
| Zone 9 | Late June to early September |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should chaste tree be planted?
10 ft (300 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 11½ ft (350 cm), so a group knits into one patch.
It grows 11½ ft (350 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many chaste tree plants do I need?
Usually one. At 10 ft (300 cm) across, it is a plant you place, not one you mass. For a hedge or screen, set them 10 ft apart: two plants for a 10 ft run.
In the bed above, the planner used one in one group.
Is chaste tree poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Is there a native plant like chaste tree?
Chaste tree comes from Mediterranean to Pakistan. These North American natives come closest to doing its job:
- Winged sumac: the same job in a bed; 20 in narrower, flowers late July to late August.
- Oceanspray: the same job in a bed; 3½ ft narrower, flowers mid June to mid July.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Do deer eat chaste tree?
Mostly not. NC State lists it as resistant to deer. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
Will chaste tree spread?
It seeds itself about; the risk of it taking over is moderate. Self-seeds in warm climates, and is listed as invasive in parts of Texas. Cut off the spent flower spikes there.
What flowers after chaste tree?
Chaste tree is over by early September. These start as it finishes and carry the same spot on, so it never goes flat:
- Pink muhly grass: from mid September to early November, 3 ft tall, to stand in front of it and cover its fading stems (a recorded partner).
- Maximilian sunflower: from early September to mid October, 8 ft tall, to stand in front of it and cover its fading stems.
- Garden chrysanthemum: from mid September to late October, 24 in tall, to stand in front of it and cover its fading stems.
What does chaste tree look like in winter?
Chaste tree drops its leaves and stands as bare branches. That is when to see its shape, and to prune it if it needs pruning.
Is chaste tree good for bees and butterflies?
Chaste tree is visited by pollinators, bees, butterflies and songbirds.
In these guides
- Salt-tolerant plants for roadsides and coasts
- Pet-safe plants for a sunny border
- Plants for butterflies
- Plants for bees
- Plants that feed garden birds
- Plants with spires: vertical accents
- Plants for a white garden
- Silver and grey-leaved plants
Every fact on record
- Type
- Shrub
- Size
- 11½ ft (350 cm) tall, 11½ ft (350 cm) wide
- Plant
- 10 ft (300 cm) apart
- Height class
- Super tall (over 6½ ft)
- Place in the bed
- Back
- Flowers
- Early July to early September; upright spires; lavender, white, pink
- Leaves
- Fine texture, deciduous; grey-green
- Shape
- Vase-shaped, self-seeding
- Hardy in
- USDA zones 6 to 9
- Light
- Full sun
- Soil
- Average, dry and sharply drained
- Water
- Low
- Feeding
- None needed
- Family
- Lamiaceae
- Comes from
- Mediterranean to Pakistan
- Attracts
- Pollinators, bees, butterflies, songbirds
- Stands up to
- Deer, drought, heat, salt
Checked against NC State Extension. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.