How to Prune Lavender
Well, it's that time of year! As everything greens and comes back to life from the bleak of winter, it is time to plan for pruning your lavender plants. Pruning will help your plants grow fuller with more branches and maximise blossom production for the lifetime of your plants.
Tips for successful pruning:
(1) Prune lavender only in the spring, while the plant is still in winter dormancy or once green growth is noticed, but prior to bud formation, if possible (usually the month of May). Do NOT prune lavender in the fall in northern climates, as this may kill the plant.
(2) Prune up to 1/3 the branch's length. Do not prune more than 1/3 per year. IF, however, a branch is dead or mostly dead, you may prune the branch all the way back to the core. [Take care, as in our northern climes, the plants are slow to appear alive — don’t deem a plant to be “dead” until at least mid-June!]
(3) TIPS: a truly dead branch will be brittle and break when you bend it. If it bends, it’s still alive. Also: if an entire plant is truly dead, there will be a slight browning or blackening of the thicker stems at the base and they will be rotten and break or pull away easily.
(4) If you are not sure, there are two ways to check whether a branch is alive or not: firstly, the snap test - try to snap a branch starting at the tip and work successively down the branch. If the branch becomes pliable down the branch, that is where it is alive. Secondly, the scratch test - if you scratch with a fingernail on the suspect branch, and see green, it is alive! It may not seem so, but give it a bit of time. When it comes to lavender, patience is definitely in order.
(5) Light, cosmetic pruning throughout the summer and early Fall is OK, but save heavy pruning until Spring. It's OK to snip dead flower stalks any time.
Best wishes for a successful lavender growing season!