Hello Fellow Readers,
At last, the big cleanup. Curt and I spent eight hours cleaning up branches, sticks, and wheelbarrows of hickory nut hulls. The critters ate the nuts and left the husks. Talk about poor table manners. Then there were the bucket loads of cones, a sign our hemlocks are happy.
I met with Jeanne of Blairstown, NJ, to coach her on early spring cutbacks. First, we cut down her ornamental grasses left dry overwinter a few inches above the ground. Hedge trimmers or a chainsaw, for those braver than I, are perfect tools for the task. Then, of course, we removed any unsightly dry plant debris from last season. It’s the woody perennials or semi-shrubs such as butterfly bush and lavender that are most confusing to folks on how to prune them. So here’s the skinny:
Rejuvenate Butterfly Bush each Year
Each year, to rejuvenate butterfly bush (Buddleia davidii), cut them down to six to eight inches above ground level. Then there’s the late-season glory of asters such as ‘Purple Dome’ (Symphyotrichum novae-angliae), whose deadwood should be removed. Finally, with hydrangeas and clematis, wait until new growth emerges before pruning back the deadwood. Be patient as this year is an anomaly of new life starting later.
How to Prune Lavender
Pruning lavender takes some finesse just as growing it does unless you have well-drained soil, full sun, and good airflow around the plants. To improve vigor and extend their life, they are best pruned each year heavily. You can prune lavender after the bloom or up to mid-spring without forgoing this year’s bloom. And while you’re at it, you can use the cuttings to propagate new plants by dipping the ends into rooting hormone and starting them in a sandy potting mix kept moist.
English lavender (Lavandula angustifolia), which Jeanne has around her herb garden, is the most common and toughest lavender often used to form a low hedge. To keep it compact, cut English Lavender by two-thirds, or to three nodes above the bare wood, in mid-August, allowing new shoots to harden off before winter. Then tidy them up with a light pruning in April.
When tending to plants that have not been heavily pruned each year and have become overly woody, you’ll need to phase in pruning to rejuvenate the plant. Trim each branch by a third or a half, never down to the brown wood, ensuring viable leaves remain on the plant. Thin out the oldest stems to encourage new growth. Then prune lightly again in the fall to shape the plant.
The later blooming Lavandula x intermedia have longer flowering stems, which are lovely flowing with the wind. They are less tough, though, and cannot be pruned to the leafless bare wood. They are best cut in late August to the mound of foliage below their spent flowering stems.
Remember, Lavender won’t rejuvenate on old wood. So, if that’s what you are left with, it’s time to replace your deadwood with something new. Sound familiar? Garden dilemmas? AskMaryStone@gmail.com and your favorite Podcast App.
Column updated 6/4/21
Link to other helpful tips in Reasons to Prune
‘Phenomenal’ Lavender (Lavandula x intermedia) is a relatively new introduction exceptionally tolerant of heat, humidity, and harsh winters. It’s what we planted in Ann’s garden in Scotch Plains, NJ, pictured here. Not only an avid gardener, but Ann is also an extraordinary photographer and kindly shared her photos with us. (Thanks, Ann!)