Pruning plants is vital if you want to keep plants healthy, shapely, and under control – but when is the best time to do it? Well, the answer isn’t straightforward because it varies depending on the plant. For many, it’s best to avoid pruning in the fall because it can stimulate new growth that will be damaged by cold. On the other hand, there are a few plants to prune in October, especially if you want to keep your garden looking gorgeous right through to spring.
Some of these will only need a very basic pruning session (more of a fall tidy-up, if you like), while others should be shaped or pruned back. To help you with this, we’ve created a list to guide your October fall pruning chores, so you can save the rest for late winter and early spring.
Just be sure to arm yourself with a pair of pruners (we're fond of the Felco F2 Pruning Shears on Amazon), a pair of Amazon's puncture-resistant gardening gloves, and a bag for your clippings before you get started on these plants...
1. Most Herbaceous Perennials
Not all perennials need to be cut back in the fall. In fact, there are more than a few good reasons to leave some in place; ornamental grasses provide winter visual interest and shelter for small animals, while seedheads on coneflowers and black-eyed Susan feed birds in winter.
On the other hand, many herbaceous perennials are at risk of developing and spreading fungal diseases if you leave their dead foliage in place too long. Iris, hollyhock, phlox, peonies, bee balm, and any others that show signs of powdery mildew or other types of fungus belong, then, on your list of plants to prune in October.
2. Lavender and Rosemary
If you grow these woody, Mediterranean herbs, it’s a good idea to trim them back in the fall. The best time to prune lavender and rosemary is after they have finished flowering but before winter begins.
Your pruning should include deadheading and tidying, but also general shaping. Be careful to avoid trimming old wood, as this can result in the plant dying.
Tender lavender types can be left alone until spring.
3. Summer-Fruiting Berries
Raspberry, blackberry, and gooseberry can all be trimmed or pruned in October, but only if they are summer-fruiting varieties. Be sure you know your type and take care to cut the year’s fruiting canes all the way down to the ground.
And remember, removing the dead wood helps prevent disease spread and makes room for next year’s growth.
4. Knock Out Roses
Pruning roses is usually best done during late winter and early spring dormancy. However, while any type of rose can be cut back pruned in the fall if they've become overgrown, Knock Out roses develop flower buds on new spring growth, making them ideal plants to prune in October as you won’t risk next year’s blooms.
Prune Knock Out roses this time of year by about one-third for the best results. Everything else? While taking them back by just a few inches can help prevent winter damage from heavy snow or ice, this is best done later in the fall.
5. Southern Magnolia
For southern gardeners, October is the best time to prune magnolia trees. Their flowers often persist well into fall, so don’t start trimming too early or you’ll miss the show.
Once the flowers have faded and the tree is done blooming, you can prune out any damaged or diseased branches and also shape the tree. Avoid pruning southern magnolias in winter, as they can bleed sap at the cuts.
It might be easier to use something like Tabor Tools' GG12A Anvil Lopper with Compound Action from Amazon for this one.
6. Gardenia
Gardenia is another one for southern and warm climate gardeners to add to their list of plants to prune in October. Like the southern magnolia, gardenia plants bloom in summer and often well into the autumn.
Avoid pruning gardenia until the flowers are spent and no more blooms open. Trim back leggy, damaged, or unhealthy-looking branches and provide any general shaping the tree needs.
7. Panicle and Smooth Hydrangeas
The timing of pruning hydrangeas depends on the type, as some bloom on old wood while other types bloom on new wood. If you prune at the wrong time, you can reduce the number of flowers that develop the following season.
Old wood bloomers, like mophead and oakleaf hydrangeas, should never be pruned in the fall. However, new wood hydrangeas, like smooth and panicle types, work as plants to prune in October.
Start by deadheading old flowers, which will help new blooms grow later, and prune to maintain the shape of your hydrangeas as well. Remove overgrown, leggy, or damaged branches. Wait to do a harder prune (up to one-third of the plant) for late winter or early spring when the shrub is dormant.
8. Shrubs and Trees with Suckers
Late fall pruning should be avoided for many overgrown shrubs and trees due to the potential for damage to new growth. However, you can make an exception for suckers, aka the thin shoots plants send up around the plant’s base. Many shrubs create suckers, which can form unsightly colonies or even drain nutrients from the main part of the plant if not removed.
Some of the common landscape specimens that produce problematic suckers include dogwood, black locust, lilac, forsythia, sumac, witch hazel, and many fruit trees. Do a thorough fall cleanup of suckers by cutting them off at the base wherever you find them. Dig down a little, if necessary, to find the point of origin of each sucker for the best results.
Fall pruning doesn't have to be a big chore, so long as you know which plants to prune in October. The rest? You can tackle them later.
