fall pruning

Fall Pruning 101

The season is winding down and fall cleanup is imminent in many of our gardens. If you plan to cut your plants back for winter, make sure you do so thoughtfully. Many of our favorite landscape plants don’t need a fall pruning. In fact, cutting them back might mean no flowers next year, and that would be terrible.

An additional consideration when it comes to pruning is timing. In general, it’s best to wait until plants have gone dormant to cut them back. This year’s extended frost-free fall might have some of you chomping at the bit to get your garden checklist completed, but be patient with the pruners! Before you get chop-happy in the garden, read our quick guide on what not to prune.

Drop the Shears!

Spring bloomers should be left alone entirely so that you don’t cut off next year’s flower buds. Lilacs, rhododendrons, forsythia, serviceberries, weigela, elderberries, azaleas, big leaf hydrangeas, magnolia, and spring blooming perennials don’t need a fall pruning. If you must prune these types of plants, it is best to do so right after they are done blooming. 

Lilac pruning
Lilacs set their flower buds on the previous year’s growth. If you want flowers, no fall pruning!

Recently installed plants should be left alone for their first winter. These plants need time to establish and settle in before any significant pruning should be completed. Pamper them with mulch and regular watering up until the ground freezes. Perennials weather their first winter better with leaves protecting their crown, so wait until spring to clean up dead foliage. 

heuchera pruning
Heuchera is happier without a haircut..

Chop Away

Herbaceous plants that are prone to problems like mildew (think peonies, bee balm, tall phlox) benefit from removing infected foliage with a fall pruning. Removing the diseased foliage discourages pathogens from overwintering on the ground and coming back in full force next year. Wait until a killing freeze has touched the foliage and then cut it away.

peony
Cut peony foliage after it has frozen.

Cut spent flowers off of hydrangea trees before the first snowfall so that branches don’t crack under the weight of the snow. Established shrubs that bloom on new wood or have later bloom times can be cut back if they’re overgrown. It is best to wait until the plant has gone dormant (a good sign is that it has dropped all of its leaves) before giving it a haircut.

Hydrangea pruning
Hydrangea tree pruning.

As always, make sure you have sharp, clean tools for pruning and don’t go overboard. Gardeners can fall victim to the old “I cut it twice and it’s still too short” just as easily as anyone.