When is the best time to prune or trim shrubs in NZ?

Got a request the other day to trim a Griselinia hedge in May. My advice to the client was to leave it until Spring. Why? Isn’t Griselinia a hardy plant that will cope with an autumn/winter trim?

Well, that’s true. It will cope with a light trim in May but will it thrive? How would you like to get a haircut and then stand out in the cold? Of course you wouldn’t because it wouldn’t be conducive to good health.

As a general rule shrubs prefer a spring prune or trim. That applies to evergreens, not winter dormant plants like roses or gooseberries (hydrangeas are another story which I won’t go into here). Why? The cuts heal faster, the plant puts on new growth to replace the old growth, the danger of frost has passed, and you will get denser, bushier plants.

One caveat - do not prune or trim flowering plants when they are in flower. Trim when the plant can put its energy into new growth not propagating itself.

So back to our Griselinia. By all means give it an early spring trim or a mid-spring hard prune. It is a hardy plant. Other plants like buxus, give it a while (I wait until October). Gives the shrub the plant a chance to put on some new growth and photosynthesise a bit.

Hope that’s helpful :)