13 Plants You Should Never Prune in Fall
Many gardeners mistakenly grab their pruners as part of fall cleanup, but autumn pruning can inadvertently cause major problems for your plants. Cutting back trees and shrubs too late can hinder winter hardiness and reduce flowers next year. Gardening expert Logan Hailey explains the top 13 plants to avoid pruning this fall and what to do instead.
With its breezy nights and vibrant changing colors, the rush of autumn is a sign to slow down and prepare for a restful winter. But first, we want to ensure our landscape is prepared for the cold. As you put your garden beds to sleep and rake leaves into piles for mulching or compost, you may wonder if you should prune your perennials, shrubs, and trees as part of your autumn cleanup regimen.
Surprisingly, fall pruning can be a huge mistake. It can severely reduce flower and fruit production in the spring and could even kill your plants! Let’s dig into 13 plants you should never prune in the fall and why autumn is the worst time for pruning.
Why Not to Prune in the Fall?
Pruning too late in the season can damage your plants and reduce vigor for the next year. Pruning encourages new growth, and the fragile new stems, branches, and buds won’t properly harden before the first frost.
This can severely weaken your plants and make them more vulnerable to diseases. For flowering shrubs and fruiting trees, autumn pruning can greatly reduce your spring yield of blossoms and fruits.
What Plants Should You Not Cut Back In the Fall?
Almost every landscape perennial should be left to enter dormancy in autumn naturally. Still, leaving spring-blooming shrubs, flowering fruit trees, and cold-sensitive plants alone is particularly important.
You should only sparingly cut off damaged or diseased parts and always use clean, sterilized pruners. Any major pruning could be disastrous for the plants you have so lovingly tended all season long!
Here are a few reasons why you should avoid cutting back these specific groups of plants in the fall:
- Spring Blooming Shrubs: Plants that flower in early spring, like lilacs and forsythia, typically form their flower buds in autumn. If you prune late in the season, you’ll remove the buds and reduce or entirely prevent the springtime floral show.
- Flowering Fruit Trees: Always postpone fruit tree pruning until late winter or early spring when the plants are fully dormant. Fall pruning can reduce winter hardiness. Moreover, cutting fruit trees creates fresh wounds where pathogens may enter during the cool, wet weather of winter. Bacteria and fungi can overwinter in limb cankers and spread via rain splash. For example, the risk of fire blight in apple or pear trees is severely increased with fall pruning.
- Evergreen Trees and Shrubs: Cutting back evergreen or coniferous plants in fall is a bad idea because it interferes with their natural hardening-off process. They become more susceptible to winter damage and infections that can enter through exposed wounds. They may also lose too much tree sap, which contains vital nutrients and minerals for spring growth.
- Cold-Sensitive Plants: Avoid pruning any tender perennials or plants that are only marginally hardy in your zone. They need the protective cover from their foliage, and pruning could expose them to harsher winter conditions that kill or stunt the plant.
- Perennials With Seedheads: Some herbaceous perennials like black-eyed Susans and coneflowers (Echinacea) produce seeds that serve as an important food for native birds during the winter. If you cut back the plants before they can form their seedheads, local wildlife may be forced to navigate elsewhere, reducing the biodiversity of your garden.
- Fall-Blooming Plants: Fall bloomers, such as asters and sedums, should be left to add winter garden interest and habitat for beneficial wildlife. They are better pruned in late winter or early spring after their fall show is complete.
13 Garden Plants to Avoid Pruning in Autumn
If you prune in the fall when your plants prepare for dormancy, it signals them to redirect their energy toward new growth. The new growth is extra vulnerable to frost damage because it hasn’t had sufficient time to harden off.
Fall pruning also disrupts the plant’s innate tendency to funnel its autumn energy stores toward the roots. It is especially important to leave these 13 plants to enter dormancy in peace.
1. Flowering Fruit Trees
Autumn pruning is the most disastrous for fruit trees, particularly if you live in a cold climate. Fruit trees like apples, pears, cherries, plums, peaches, and nectarines should never be pruned in the fall. Instead, wait until late winter or early spring when the plant is fully dormant. The only exceptions are citrus and tropical trees in zones 11-12 because these areas do not typically experience frost.
There are many reasons not to prune your fruit trees in autumn, but the most obvious is the potential to majorly reduce fruit production the following year. Additionally, you risk weakening, stunting, or even killing a young tree if you harshly prune it before winter dormancy. You can understand more about your fruit trees by digging into the following primary reasons for avoiding fall pruning.
Loss of Flower Buds (Reduced Fruit)
Buds are the main reason you want to avoid fall pruning on most fruit trees in temperate climates. These little nubs along tree branches are the beginnings of future flower, fruit, and leaf production.
A bud is a cluster of stem cells called meristematic tissue, which proliferates into new plant parts. Buds form at the tips of stems or where a leaf stem joins a branch. If you have ever taken cuttings from a plant, you are probably familiar with cutting beneath a node to ensure proper rooting. A node is the location where new buds grow.
Fruit trees produce two types of buds:
- Flower and Fruit Buds: These are the start of flowers and fruit. They form in mid-summer to mid-fall when the plant’s vegetative growth has slowed, then they burst into bloom the following spring.
- Wood or Growth Buds: These buds develop into new shoots and leaves. They form after fruiting in the spring and contribute to the plant’s new foliage growth in the summer.
Because fruit trees set their flower buds in the fall to prepare for next year’s blooms, pruning may inadvertently remove these vital buds. It is very difficult to avoid buds during the pruning process. If you cut off the branches with developing flower buds, you reduce your tree’s ability to flower, thus reducing the spring harvests of fruit. Let the buds hang out through the winter so you can enjoy more juicy fruit next year!
Reduced Winter Hardiness
As we mentioned above, pruning stimulates new growth. If you cut your fruit trees in fall, the newly formed branches won’t have time to harden off before winter arrives. The tender new shoots and stems are very susceptible to frost damage.
Stimulating new growth reduces the tree’s overall winter resilience, which can be detrimental if you grow a species on the margins of its hardiness zone.
For example, fig trees are usually only hardy in zones 8-12. Zone 7 gardeners can grow cold-hardy fig varieties outdoors, but fall pruning can dramatically reduce the tree’s ability to overwinter.
Disease Vulnerability and Spread
The moist, cool weather of fall is prime time for fungal spores and bacterial infections to spread. Pruning creates fresh wounds in the tree, offering many entry points for pathogens.
The fruit tree often doesn’t have sufficient time or energy to heal the wound properly before hard frosts hit. This means it will have to cope with an exposed “sore” all winter, reducing its overall health and contributing to the spread of disease.
To be clear, diseases are not caused by fall pruning. Rather, they are likelier to take hold of a weakened or exposed tree. Examples of diseases exacerbated by fall pruning include:
- Fire Blight: This bacterial infection affects apple and pear trees, creating a bacterial ooze from cut surfaces that can quickly spread through a small orchard.
- Silver Leaf: This fungal disease affects stone fruits like plums and cherries. The fungus can enter through pruning wounds exposed to autumn air and moisture.
- Cytospora Canker: Another fungus, this disease affects many species, including peaches and cherries. It accelerates its spread after fall pruning because it attacks weakened trees, causing sunken, discolored lesions in the branches.
Reduced Winter Energy Storage
Autumn is iconic for fallen leaves, but what those leaves really represent is a tree’s transition into dormancy. The tree is sucking all its vital nutrients into the trunk and roots and dropping its leaves so it doesn’t have to support excess growth during the harsh winter.
You can imagine this process as similar to a squirrel putting away acorns for the winter or a bear getting extra fat before it hibernates. You wouldn’t want to confuse these creatures by distracting them from their winter preparation efforts. Pruning a tree at this time can disrupt the natural cycle of slowing down because it signals the tree to put its resources into new growth rather than its winter stores.
2. Rhododendrons and Azaleas
If you love vibrant rhododendron and azalea flowers, do not prune them in the fall! For the most beautiful spring show, these woody shrubs are best left to their own devices throughout the winter.
Like fruit trees, these shrubs produce buds in late summer and fall. If you prune branches before winter, you could remove next year’s flowers.
The best time to prune these pretty acid-loving shrubs is usually in early spring after the plants bloom. Professional landscapers sometimes prune in late winter while the plant is still dormant to intentionally reduce the flower set. If you prune ultra-floriferous rhododendrons before blooming, it will thin the flowers but help maintain the vigor of a weakened plant.
Either way, these shrubs only need minimal pruning. You should very sparsely remove dead and sickly branches and do a little shaping; otherwise, let them grow naturally.
The vibrant yellow flowers of forsythia are a beautiful sight after a long, dreary winter. These beautiful fiery shrubs are one of the first signs of spring. However, autumn pruning may reduce the flower show. These plants bloom on old wood and set their flower buds the summer before blooming.
These fast-growing shrubs can grow up to 10 feet tall and certainly need pruning to stay under control. An unpruned forsythia can become very leggy and even start sprawling on the ground. To avoid this, prune forsythia in the spring after the blooms fade.
You can cut a mature shrub back by one-fourth to one-third of its growth. However, you should allow it to maintain its natural arching habit. For an extremely overgrown forsythia, you may need to sacrifice one or two seasons of blooms by brutally cropping the shrub down to 4-6” above the ground. It will rejuvenate itself with new shoots but may not flower for 1-2 years.
No matter how you want to shape your forsythia shrub, do not do anything to it in the fall! Wait until it has bloomed, then grab your shears.
While some plants are cut back after their floral show is complete, chrysanthemums are an exception. You do not want to prune these shrubs in the fall. Instead, wait until late winter or spring to cut back the stems.
Chrysanthemums need their leaves to produce energy as they shift into dormancy. They benefit from natural stem dieback. While it may look unsightly for a few months, it is far better for the plant’s health.
The weird caveat is you can still deadhead your mums during fall. This means you only cut off the withered flowers but leave the rest of the plant alone. By deadheading a chrysanthemum bush in early fall (August or September), you encourage a longer bloom time into late September or early October.
Garden mums famously bloom in autumn and have become the unofficial seasonal flower for high school homecoming celebrations in the southern United States. In my home state of Texas, we created elaborate homecoming mums for cheerleading events. Many football players would gift the mums to their girlfriends. Although many of the mums used today are artificial flowers, southern gardeners still enjoy giant mum blooms until Halloween or later, thanks to deadheading.
What is the moral of the story? These pretty fall-blooming shrubs benefit from maintaining some foliage through the winter. You can cut off dead fall flowers, but not the branches and stems.
Like fruit trees, lilacs set their flower buds in autumn. You’re probably growing these shrubs for their gorgeous flowers, so you don’t want to cut off the flower buds! Fall pruning of lilac can reduce spring bloom and make for a sorely disappointing floral display. It also disrupts the winter hardening process of the lilac branches.
Lilac bushes are remarkably hardy and grow in regions as cold as zones 2 and 3. In fact, they need a nice chill period to produce their deliciously fragranced flowers. Still, some varieties are more frost-tender than others, and you do not want to disrupt the plant’s transition into dormancy by triggering new autumn growth.
The best time to prune lilacs is spring after the current flowers have faded, often in April, May, or June. There is a relatively short period of time between the death of old flowers and the formation of new buds. Pruning later can cut off many or all of next season’s blooms.
6. Oakleaf Hydrangea
While many hydrangeas are pruned in late winter and early spring, oakleaf hydrangeas should only be pruned after they finish blooming during summer. Don’t wait too long; you may prune off next year’s flowers. Fortunately, these varieties don’t often require much pruning. If you forgot to cut them back in summer, it’s best just to let them be.
Also known as Hydrangea quercifolia, oakleaf hydrangea shrubs bloom on old wood. Old wood blooming hydrangeas produce flower buds in late summer or early autumn on the wood that grew the previous season. Those buds must survive a cold winter freeze and continue growing the following year.
Basically, this means they should only be pruned after flowering has occurred. Like fruit trees and lilacs, fall pruning could inadvertently remove the flower buds for the next season. If you cut back oakleaf hydrangeas in the autumn, you may not get the beautiful long panicles of flowers you crave to see in spring.
So, oakleaf hydrangeas should only be pruned right after they bloom. The only time you should prune oakleaf hydrangeas during fall is if you are removing dead, damaged, or diseased stems from the plant. If you have an overgrown or mangled shrub, you may have to cut the whole plant down in late winter or early spring and sacrifice a year of blooms for the sake of shrub rejuvenation.
Viburnum is another popular and beautiful spring-blooming shrub that sets flower buds in late summer and early fall. Pruning these attractive shrubs can drastically reduce the floral display next spring. Are you noticing a pattern here?
This shrub only needs a nice blanket of mulch in the fall. You don’t need to do anything else to your autumn viburnums!
The best time to prune and shape your viburnum shrubs is after flowering in late spring and early summer. Still, you don’t want to over-prune, or you will miss out on the pretty, drooping berries that most varieties produce in autumn.
Some gardeners thin this plant during the dormant season of late winter, but this reduces overall bloom quantity. Regardless, avoid cutting the plants in late summer or fall unless you have to remove diseased or damaged branches.
Spirea are enthusiastic growing brushes that aren’t as sensitive to pruning. Still, fall pruning poses a risk in cold zones because the late-season flush of new growth can cause winter damage.
Keep your pruners in the tool shed while your spirea drops its leaves and enters its dormant period. Avoid fertilizing or heavily cutting because it will cause new flushes of tender growth. All you need to do for this shrub in fall is mulch with leaves, straw, or bark.
Many Spirea species bloom on last year’s growth, which means autumn pruning can reduce the flower display next season. According to Oregon State University Extension, spring-flowering varieties are best cut back right after they bloom. Summer-flowering varieties are best cut back in late winter when the shrub is dormant.
Renewal pruning, or cutting back an overgrown shrub almost down to the ground, can also be done in early spring to promote whole plant rejuvenation.
9. Crepe Myrtle
Southern horticulturalists assert that crepe myrtles are among the most improperly pruned trees! They jokingly call them crepe murders! But truly, so many people make mistakes with these gorgeous trees and inadvertently cause an uglier landscape. The most common mistake is “topping” the tree (cutting off all its upper branches).
Cutting back a crepe myrtle tree in autumn can cause severe winter damage. It removes the plant’s natural winter protection and exposes vulnerable young stems to frost. The extra growth is needed to help the plant survive the cold months.
Moreover, fall chopping makes for an unsightly view in your winter yard. A leafless crepe myrtle tree with its natural stem formation is much more aesthetically pleasing than one with its head chopped off.
Only prune crepe myrtles during late winter when they’re leafless. January and February are common months to cut branches from these trees selectively, but it depends on the region and intensity of the winter. These trees bloom on new growth, so winter pruning won’t reduce the blooms. In fact, it can increase flowering!
10. Lily Magnolia
Another popular deciduous shrub or small tree, the lily magnolia, produces precious pink or purple blossoms in early spring before the leaves appear. Like lilacs and rhododendrons, the flower buds of this magnolia form the season before they bloom. If you cut back a lily magnolia in late summer or fall, you sacrifice the flowering show for the following spring.
Instead, trim off dead or damaged branches in summer and deadhead the spent flowers after blooming. Light pruning in midsummer after the floral show is ideal because you won’t harm the foliage growth or disrupt next year’s flower buds. The plant will have plenty of long, warm days to rejuvenate any cut branches and form new buds before the cold of fall and winter.
The trend continues: camellia shrubs start to develop their flower buds for next year during the mid-summer of the season prior. If you prune your camellia this fall, you will remove the vital buds that grow into beautiful, swirly blooms next spring.
Depending on your growing zone and variety, some camellias may bloom earlier or later in the season. If unsure, avoid pruning until you identify your camelia cultivar and check with your local extension service.
When in doubt, the safest time to prune is—you guessed it!—right after the flowers have faded.
12. Butterfly Bush
Many people mistakenly want to prune butterfly bushes in the fall, but it’s best to wait until late winter or early spring. Waiting to prune your butterfly bush is especially important in cold climates because the plant becomes more susceptible to frost damage after cutting it back.
Fleshy new shoots may have exposed cells that collapse when the water inside them freezes. Moreover, older stems can collect water in the hollow center of a cut and then split when frosts arrive. The biggest risk with pruning this quick-growing shrub is reducing its winter hardiness.
The dazzling butterfly bush flowers are, unsurprisingly, super popular in butterfly gardens. If you want to attract the maximum amount of pollinators to your Buddleia shrub, let the plant naturally move into dormancy during fall and give it a nice haircut in spring. Pruning certainly can increase flowering, but you don’t want to encourage new growth until the weather is sufficiently warm.
As a rule of thumb, don’t prune until you see green leaf buds on the butterfly bush stems and the threat of frost has passed.
13. Japanese Maple
Japanese maples are coveted for their unique shape, vibrant autumn colors, and use in Bonsai displays. But fall pruning can pose a major issue for these gorgeous mini-trees. The primary issue here is bleeding sap. Dripping sap not only looks ugly, but it attracts pests and diseases and can make it more susceptible to winter stress. The open wounds are portals for infections.
Additionally, Japanese maples are appreciated for their delicate, intricate branch structure for the winter landscape. Fall pruning can reduce the visual appeal and cause unsightly new growth that dies back in frost.
If you are growing Japanese maple in a container, avoiding messing with it in autumn is especially important. Instead, let the plant drop its leaves, mulch it at the base, wrap the pot and tree with burlap, and move it to a sheltered location like an unheated garage or porch for it to overwinter.
Heavier pruning is best done in late winter or spring during the dormant stage when the sap is less likely to flow. You can remove damaged or diseased branches throughout the summer during its main growth stage.
Exceptions to the Rule: Only Fall Prune If…
While most of these plants can be severely harmed by fall pruning, diseased or damaged branches are the main exceptions to the “no-fall-pruning” rule.
The top rule of pruning is to remove problematic branches first! We don’t want to leave diseased or infected plant material over winter. The extra moist and stagnant conditions can create a breeding ground for fungi and bacteria to travel through the garden, causing even more problems come spring.
If you notice diseased stems or branches on any plant in your garden, removing them immediately is best. Place diseased stems immediately into bags so they don’t blow spores to nearby plants if possible. Dispose of them in the trash or a burn pile, and never compost infected plant material. Use sanitized pruners and always sanitize between cuts to avoid spreading an infection from one plant to another.
Damaged Wood or Hazardous Branches
If you have a major branch or stem hanging over your house or garden, it needs to be removed before a winter storm knocks it down. Trust me, I’ve seen a giant fruit tree limb fall on a farm barn, and it was not pretty! Winter snows can cause added weight burdens on dangling or unstable branches.
Before you hunker down for winter, double-check that there aren’t any trees or shrubs with hazardous stems that need to be cut. If you must make an emergency removal, it helps to spray the wound with an organic fungicide such as copper to prevent infections.
Grab a hot cocoa instead of fall pruning! Your autumn landscape efforts just got a whole lot easier! Most trees and shrubs are best left alone in fall, particularly if they produce flower buds on the previous season’s growth. Instead, you can hang up your pruners and cozy up by the fire. You’ll need the extra energy to go out and prune during the chill of late winter or early spring.