How to Prune Lavender in Canada
Two cuts a year, both into green growth only: the spring shape-up and the trim after the first bloom.
How to prune lavender comes down to one rule: always cut into leafy green growth, never into bare wood. The Royal Horticultural Society notes that lavender does not break new growth easily from old stems, so a cut into the woody base often leaves a dead stub.
In Canada the timing matters as much as the cut. The main prune waits until spring, when new growth shows at the base, and the plant is left standing through fall and winter, when its woody stems help protect the crown.
Pruning lavender at a glance: spring (about April–May, once green shoots show at the base): cut back by one-third to one-half, leaving green leaves on every stem. Summer, right after the first bloom: remove spent flower stalks and a little leafy growth. Never cut into bare wood, and do not prune in fall.
Just need the dates? See When to Prune in Canada for every plant in one table.
The Spring Prune
Wait for proof of life. When new green shoots appear along the lower stems, usually April to May depending on where you live, you can see exactly which parts survived the winter. Cutting earlier means guessing, and a winter-browned stem can still be alive.
- Cut out any stems that are clearly dead: dry, brittle and grey all the way down, with no green buds.
- Cut the rest of the plant back by about one-third to one-half, shaping it into a rounded mound.
- Check every stem after the cut: it must still carry green leaves below the cut. If it would not, cut higher.
- Leave the woody base alone. That framework is what the plant regrows from.
The RHS also allows a light clip in spring if growth is untidy or frost-damaged, which is the situation most Canadian lavender is in by April.
The Summer Trim After Bloom
The RHS recommends trimming lavender every year just after flowering, removing the spent flower stalks and about 2.5 cm of leafy growth, to keep plants compact. NC State Extension likewise says to remove spent flower spikes after the flowers fade.
In Canada, do this trim promptly after the first flush, in July in most of the country. It tidies the plant and, in warmer zones, can bring a lighter second bloom. Keep it light, and do not leave it until fall. Our growing lavender in Canada guide gives bloom times by city.
| Cut | When | How much | Why |
|---|---|---|---|
| Spring shape-up | About April–May, once green shows | One-third to one-half, into green | Keeps the plant compact and full |
| Summer trim | Right after the first bloom | Spent stalks plus about 2.5 cm | Tidy shape, possible rebloom in warm zones |
| Dead wood | Any time in the growing season | Back to live growth | Removes winter-killed stems |
| Fall cut | Do not | — | Stems protect the crown over winter |
Why Not Prune in Fall
The woody stems and last season’s leaves help shield the crown through freeze-thaw cycles. A plant cut back in October goes into winter with less protection, and any new growth the cut triggers will not harden off before the cold. Leave it scruffy until spring. What not to prune in fall covers other plants with the same rule.
Old, Woody Lavender
Even with yearly pruning, older lavender becomes woody, open in the middle and misshapen. The RHS advice is blunt: such plants are best replaced, because they establish quickly and cutting them back into old wood rarely brings them back. Take cuttings from the old plant in early to midsummer, as the RHS suggests, and you can replace it with its own offspring.
Pruning cannot fix a plant that is dying of wet roots. See overwintering lavender for drainage, the most common cause of winter loss in Canada.
Frequently Asked Questions
When should I prune lavender in Canada?
Twice: a main prune in spring once new green growth shows at the base, usually April to May, and a light trim right after the first bloom in summer. Do not prune in fall.
How far back can I cut lavender?
By about one-third to one-half in spring, but always leave green leaves on every stem. Lavender rarely regrows from bare, woody stems.
Can I cut lavender back to the ground?
No. Unlike perennials that die back, lavender is a small shrub that regrows from its woody framework. Cutting into bare wood usually kills that stem.
Why shouldn't I prune lavender in the fall?
The stems and leaves help protect the crown over winter, and new growth triggered by a fall cut will not harden off before the cold.
Should I deadhead lavender?
Yes. Removing spent flower stalks right after the first bloom keeps the plant tidy and can bring a second, lighter bloom in warmer parts of Canada.
My lavender is woody and leggy. Can I save it?
Usually not by pruning hard, because old wood rarely resprouts. Take cuttings in early to midsummer and replace the plant with them.
Sources
- Royal Horticultural Society — How to grow lavender
- NC State Extension Plant Toolbox — Lavandula angustifolia