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11/10/2021 11:01 PM

Don’t Make the Mistake of Pruning Too Late


If you prune a lilac bush in the fall, you’ll chop off the blooms for next year.Photo courtesy of the North Haven Garden Club

Fall is upon us once more and with the sunny days we have ahead of us, many gardeners and home owners turn their sights on fall clean-up in their yards.

It’s fine to rake up your leaves (and hopefully compost them), pull faded annuals, plant spring bulbs and tidy up your yard. With pruner in-hand, many of us can make the mistake of pruning way too late in the season.

The following is a guide to what you should not prune in the fall.

If you have ever wondered why your flowering shrubs don’t flower, it may be you pruned it at the wrong time of year. Many shrubs bear flower buds for the following season on last year’s wood, or “old wood” as its called. So if you prune now, you are cutting next year’s flowers off.

Did you know that if you prune too late in the season, you stimulate new growth, which will not have time to harden off before the first frost, which will be coming soon to our neck of the woods. This can weaken and damage the plant, so its best to leave the pruning until spring.

So put down the pruners and save yourself some work and frustration for later. So here are the most common shrubs to just leave alone in the fall. The following information is from Arricca Elin SanSone, a writer who specializes in gardening and related matters.

• Oakleaf hydrangea: With leaves that resemble an oak tree, this shrub blooms from summer to fall. But don’t cut oakleaf hydrangeas back like you do other types of hydrangeas, such as panicle hydrangeas, which bloom on new wood. Oakleaf hydrangeas bloom on old wood and never need trimming except to cut off dead branches that don’t leaf out next spring.

• Forsythia: Since many types of forsythia can get large and unmanageable, it may be tempting to hack them back in the fall. However, you’ll remove the buds that form next year’s bright yellow blooms. If your shrub has gotten too big, trim it next spring immediately after it finishes blooming. And next time, plant a new dwarf variety that will stay nice and compact.

• Lilac: If you prune in the fall, you’ll chop off the blooms for next year. It should rarely be trimmed except to cut off dead branches. Also, look for new dwarf and re-blooming varieties if you want to plant a new lilac.

• Ninebark: This is a shrub you should never prune, except to trim back any dead branches when you see them. Otherwise, leave it be so you don’t destroy its form.

• Rhododendrons: If you prune now, you’ll cut off next year’s flowers. If your shrub needs neatened up, trim immediately after the flowers fade in the spring.

• Azaleas: These also bloom on old wood, with next year’s flowers forming months after the current year’s flowers have died back. Prune only immediately after flowering if you need to shape it.

• Weigela: Don’t trim them in the fall.

• Mountain hydrangea: While it’s fine to remove dead wood, don’t do it until late spring when the plant has leafed out so you can see what you’re doing.

Visit The North Haven Garden Club on Facebook for more information. North Haven Garden Club is a member of The Federated Garden Clubs of Connecticut, Inc., New England Garden Clubs Inc., and The National Garden Clubs Inc.

Ninebark is a shrub you should never prune, except to trim back any dead branches when you see them. Photo courtesy of the North Haven Garden Club
Oakleaf hydrangeas bloom on old wood and never need trimmed except to cut off dead branches that don’t leaf out next spring. Photo courtesy of the North Haven Garden Club