Key Points
Whether to prune perennials in November depends on the type of plant.Plants with powdery mildew should be pruned in fall to prevent spread of disease.Leaving plant growth intact in spring can provide protection from winter damage.
Late season garden work often involves various clean up tasks and protecting plants from winter weather. In November, there’s still plenty to do, including perennial care. As garden plants begin to die back and go dormant, some deadheading or pruning can make the garden look neater.
While many gardeners take an all or nothing approach to pruning in the fall (cutting back everything, or leaving it all until spring), it turns out there are some plants that benefit from late autumn pruning. We asked some experts to advise on which perennials to prune in November, and which ones to leave alone until spring.
Meet the Expert
Angelika Zaber is a Lawn Care Specialist and Gardening Expert working for Online Turf in the UK.
Emma Daugherty is an experienced gardener and marketing director for the Bath Center Garden and Nursery in Colorado.
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Which Perennials Are Okay to Prune in November?
Whether November is too late to prune perennials or not depends on the species of plant you’re dealing with, says Angelika Zaber, a gardening expert with Online Turf.
Zaber suggests trimming back herbaceous perennials (like hostas and tall phlox) in November, because “otherwise, they might develop diseases such as powdery mildew.”
Some perennials, like peonies, may be a case by case basis: if there’s no sign of powdery mildew, they can be left intact until spring, but if the leaves do show evidence of this or other diseases, cut them back by late fall.
Perennials with a reputation for being hardy and robust, that can be divided in spring or fall (including sedums, species daylilies, or Shasta daisies), are sturdy enough for November pruning.
Perennial shrubs that flower in autumn can be pruned lightly in November if desired. Always trim off dead or damaged branches as soon as you notice them, as leaving them through the winter can possibly cause more damage in extreme weather.
Emma Daugherty, a gardening professional and director of marketing for the Bath Center Garden and Nursery, says light pruning of late-flowering shrubs in fall also encourages healthy growth.
Daugherty particularly recommends lightly pruning shrubs that produce spring growth on new wood, like panicle (H. paniculata) or smooth hydrangeas (H. arborescens), weigela, or rose of Sharon (Hibiscus syriacus).
Focus on pruning small branches for light shaping, or removing damaged branches, or lower branches that overlap, droop, or flop onto the ground.
Which Perennials Should Not Be Pruned in November?
Zaber recommends not pruning evergreens in November, as this can leave them unprotected from hard frost. Leaving the extra foliage intact bolsters the plant’s preparation for winter, and provides natural insulation from winter damage, including freezing temperatures, snow, ice, and wind.
Some summer-flowering perennials benefit from having their foliage left intact until new growth starts to emerge in spring, including coral bells and astilbes: the faded foliage offers extra protection for the roots.
Zaber thinks gardeners shouldn’t prune perennials with active seedheads or berries, as these “provide food for birds and other wildlife during the time when the resources are most scarce.”
This includes coneflowers (Echinacea), black-eyed Susans (Rudbeckia), many viburnums, and beautyberry (Callicarpa).
Deadheading Vs. Pruning
Deadheading and pruning may seem like very similar activities, but their purposes are different.
Deadheading refers to removing spent flowers or foliage, usually to stimulate new flower buds or make a plant look neater. Pruning often means cutting back a plant’s growth to shape it or control its size, as well as removing dormant or damaged stems or branches.
Deadheading or pruning in November can leave some plants exposed to frost or wind damage, while for others it can help prevent ice build-up. Large leafed plants like hostas, comfrey, or foxgloves, for example, can become encased in ice during a slow springtime thaw.
What to Do If It’s Too Late to Prune
If you run out of time before cold temperatures arrive, you can wait and cut back perennials in spring. Many perennials perform well if pruning is done in early spring just as new growth starts to show, and some can be pruned in late winter (like butterfly bush).
When pruning shrubs, says Daugherty, don’t cut more than a third of their growth at one time, even when they are dormant.
There are other ways to care for your plants in November apart from pruning or trimming. Daugherty recommends reducing watering and feeding, to help perennials prepare for winter dormancy.
She also encourages mulching to protect roots from frost damage. Waiting to mulch until after the first hard frost allows the plant to build up some more resistance to cold temperatures.
Use lightweight organic mulch like shredded pine bark, or materials as straw, shredded leaves, nut hulls, or pine needles. Wood chips can absorb a lot of moisture and thaw slowly in spring, so if using wood chips, layer them no more than two inches thick.
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