Prune chaste tree in late winter because it flowers on new wood. Cut it as a shrub, train a few trunks as a small tree, or take freeze-killed stems to the ground.
Cut it in late winter — it flowers on new wood
| Factor | Recommended | Avoid |
|---|---|---|
| When | Late winter or early spring, before new leaves | Do not wait until the new shoots have already set bloom, and do not shear it in fall |
| Wood | This year's growth carries the summer spikes | Do not treat it like a lilac that blooms on last year's wood |
| How much | A hard cut is safe if you want a smaller plant | Do not shear it into a flat hedge |
| Spent spikes | Clip faded panicles if you want another flush, or if you do not want seedlings | Do not leave every fruit if volunteers are already a problem |
chaste tree sets its summer spikes on the current season's growth, so a late-winter cut does not take next summer's flowers. [1] Cut before the new leaves, while you can still see the branch structure. [2] A hard cut keeps a large plant to a modest size without stopping bloom. [3]
- Wait until late winter or early spring, before the buds break.
- Cut dead, crossing, or freeze-killed stems first, back to live wood or to the crown.
- Shorten last year's shoots by a third to a half if you want a denser shrub, or take them lower if you want a smaller plant.
- Make each cut just above an outward bud, and stagger the heights so the top is not a flat line.
- Clip spent flower spikes in summer if you want another flush, or if you do not want fruit.
When do I prune chaste tree?
Late winter or early spring, before new leaves. It flowers on new wood, so that cut does not take the summer spikes.
Pick a shrub, a small tree, or a cut-to-the-ground plant
Decide the form before you cut, because the same plant can be a multi-stem shrub, a small tree on a few trunks, or a dieback perennial after a hard freeze. [4]
- For a shrub, keep several stems from the crown and shorten them in late winter so the plant stays full.
- For a small tree, pick two or three well-spaced trunks, remove the lowest suckers, and raise the canopy to the height you want to walk under.
- After a freeze that killed the top, cut the dead stems to the ground. New shoots from the crown still flower that summer.
- Do not shear the outline into a ball. Thin or head to a bud so light reaches the inside of the plant.
Sun, drain, and watering stay on How to Grow Chaste Tree.
Can I cut it to the ground?
Yes, after a freeze has killed the top, or if you want a low flush of new wood. The new shoots still flower that summer.
If the plant is a tangle of crossing stems, take the worst of them in late winter and leave a few well-spaced trunks.
FAQ
Do I have to prune every year?
No. An unpruned plant still flowers. Prune when you want a smaller size, a tree form, or a cleanup after freeze damage.
Should I deadhead the spent spikes?
Clip faded panicles if you want another flush, or if seedlings are already coming up. Leaving the fruit is fine if you do not mind volunteers.
Related guides
Recommended plants
References
- [1] NC State Extension -
https://plants.ces.ncsu.edu/plants/vitex-agnus-castus/ - [2] NC State Extension -
https://plants.ces.ncsu.edu/plants/vitex-agnus-castus-shoal-creek/ - [3] University of Arkansas Extension -
https://www.uaex.uada.edu/yard-garden/resource-library/plant-week/chaste-tree-08-17-07.aspx - [4] Walter Reeves -
https://www.walterreeves.com/landscaping/chaste-tree-vitex-pruning/
This note is part of Vitex Guides.
More pruning timing notes by plant live in Pruning Guides.
Updated: Reviewed by Bosquelle Editors