Did pruning lavender plants cause them to die or go dormant?
We are seeking assistance with our lavender plants. They were planted three years ago and all was well until this year. In the spring, we pruned them down to the woody section and with the exception of one plant, there were no blooms. It’s uncertain whether they’re dormant or dead at this point.
It sounds as though the pruning may have been a bit too aggressive. Lavender is a perennial plant that has mature, woody tissue at the bottom and new, more succulent tissue above. The plant slowly transitions to having more and more of the woody section as its life cycle progresses. By pruning it, we gardeners slow that process, which keeps the plant producing new growth and flowers longer than it would if left to its own devices.
However, the pruning should be done only in the green shoot portion of the stems (termed “juvenile” tissue because it can grow and develop new shoot material), a few inches above the woody sections. In general, we recommend waiting until you see new growth before pruning so you can make sure you’re staying above that line. Lavender flowers on current season growth, so such pruning shouldn’t affect the flowering. If the pruning cuts go down to the woody part, you are venturing into plant material that really functions primarily as support for the plant and as a conduit for water and nutrients, but not as a bed for new tissue growth. If you haven’t seen new any green by now, I fear those particular plants are most likely dying or already dead.
If it softens the blow at all, this is a *very* common slip up by many gardeners, even experienced ones, and at least it sounds as though one of your plants survived. Pruning is a learning process, and we all learn by doing, so don’t feel too bad. A similar question appeared previously in our column and while it deals with winter dieback, there is also good information linked about where to limit the pruning.