Written By Lara Wadsworth

Microgreens are gaining popularity among growers and consumers. They are nutrient-dense, easy to produce, and can turn a profit quickly. The rising demand for efficient growing mediums continues to propel researchers to find better options beyond soil or hydroponic systems. Growing mediums may not seem like a big deal when it comes to microgreens, but studies are finding that they can have a significant impact on root health, nutrient uptake, and yield, among other things. Two studies published in 2024 have proven that coco coir (AKA cocopeat) and vermiculite are the top two growing mediums available for many reasons.

Why Fall Is the Best Time to Prune Perennials

Fall is the best time to prune perennials because the plants are going dormant, but you don’t have the hindrances of leaves or snow to block your view of the plant. When going into dormancy, plants conserve their energy and stop or slow above-ground growth. The USDA explains, “prune in the dormant season to easily visualize the structure of the [plant], to maximize wound closure in the growing season after pruning, to reduce the chance of transmitting disease, and to discourage excessive sap flow from wounds.” (page 16)

The only exception to this is trees or shrubs that flower in the early spring, like redbud, lilac, or dogwood. These should be pruned immediately after flowering in the spring to promote new wood growth that will flower the following year. For any species, remove dead or diseased branches at any time of year.

Which Perennials to Cut Back in Fall (and Which to Leave for Winter)

Most perennials should be cut back in the fall. More specifically, any plants that have had disease or pest problems should be cut back in the fall to reduce the chances of infection recurring the following season. Hostas should almost always be cut back to the ground as soon as the frost takes them. Also, cut back any plants with browning or blackened stalks that are bare and do not add visual interest to the winter garden. Some examples of things to cut back include Peonies, Daylilies, Brunnera, Speedwell (Veronica), Yarrow, Shasta Daisies, and Echinops (Globe Thistle). When in doubt, I love the Penn State Extension's website for clarification.

Avoid cutting back perennials that add beauty to the winter landscape, provide a winter food source for birds, benefit beneficial insects throughout winter, require protection, and any low-growing evergreen or semi-evergreen perennials. For example: Switchgrass, Zebra Grass, Feather Reed Grass, Irises, Blue False Indigo, Sedum, Joe Pye Weed, Echinacea, Rudbeckia, Heliopsis, many native plants, Garden mums, Anise Hyssop, Red-hot poker, and Montauk Daisy fall into these categories.

How to Tell If a Perennial Is Ready for Pruning

If you’re unsure about the perfect timing for pruning your perennial plant, look for common signs that will cue you in. Look for signs of natural dieback, such as yellowing or browning foliage. If most of the plant seems to be dying off without your help, it’s probably the perfect time for cutting it back anyway. However, you will need to understand the difference between healthy foliage dieback and disease or pest damage. If you see any abnormal spotting, pest presence, or uneven dieback, you may be dealing with a pest or disease. If that is the case, you should only cut back the affected foliage and dispose of the removed plant matter far away from your garden.

The bottom line is that, in most cases, if a plant is actively growing (putting on new leaves or flowers), it is not a good time to prune. Pruning during dormancy is your best bet for a healthy plant and a healthy garden. If you have fruit trees that are known to be susceptible to disease, consider pruning during the cold winter months of January or February. This can help avoid the spread of known diseases like Fire Blight in apple trees.

Essential Tools for Pruning Perennials in Fall

There are many guidelines out there from the USDA and various extension services. In a nutshell, you are most likely going to want:

• Bypass-style hand pruners for branches 2 cm in diameter or less
• Bypass-style lopping shears for branches 3-7cm in diameter
• Manual Pruning Saw for branches greater than 8 cm in diameter
• Chainsaw for branches larger than 10 cm in diameter (only to be used by qualified individuals)
• Spray bottle of 70% isopropyl alcohol for cleaning your tools between cuts

It is important to sanitize your tools between cuts and between pruning plants to prevent the spread of diseases, particularly fungal diseases. I prefer rubbing alcohol (isopropyl alcohol) because it can be used directly from the container without needing to dilute it, and there is no risk of harming your clothes or other tools (like bleach can sometimes do). Simply spray the rubbing alcohol on the blade of your tool and wipe it clean.

How Short Should You Cut Back Perennials?

As a general rule of thumb, most herbacious perennials need to be cut back to about 2 to 3 inches above the soil. There are exceptions for woody or crown-sensitive perennials. It is typically best to cut back the whole plant at one time. Some species tolerate cutting back better than others, while some species do best without being cut back at all between seasons. Pay close attention to the signs the plant shows and ask your local extension office if you have region-specific questions. Luckily, perennials are generally forgiving, and if you do it wrong one year, you will likely have another chance to get it right once it recovers.

For pruning landscape and fruit trees, the North Carolina State University Extension Service offers a helpful guide with detailed instructions and pictures for proper branch cutting. This guide also talks about many other species and why, how, and when to correctly prune them. If you have further questions, I recommend reading it!

What to Do With Perennial Cuttings After Pruning

Cuttings that were healthy, not diseased, or harmed by pests, can safely be composted so that their nutrients can return to your garden soil for next year’s blooms. If any cuttings have been diseased or significantly affected by pests, it is best to destroy them away from the garden, usually by fire. There is a wide variety of garden waste types, and the Royal Horticultural Society's guide on dealing with garden waste is very helpful in determining what to do. Everything from leafmould to matchstick mulching, to the benefits of log piles, this guide has it!

It is best to use the materials your garden produces within your garden, either as compost to enrich the soil or as a structure for other beneficial plants and insects to use nearby. Every year we grow gardens, those plants are pulling nutrients out of the soil and turning it into leaves, flowers, and stems. If we can return those no-longer-used plant materials to the soil, it will benefit the soil microbiome, reduce fertilizer use, and reduce the carbon footprint of your property.

Dividing Perennials in Fall: Which Plants and When

Perennials that bloom in the spring or summer should be divided in the fall, and fall-bloomers should be divided in the spring. Perennials that should be divided in the fall include peonies, poppies, daylilies, and irises. Dividing in the fall is very easy when possible because it is plain to see which plants need division, and there is less gardening work to be done in the fall compared to spring.

When dividing plants in the fall, it is critical to time it four to six weeks before the ground freezes. The plants need a bit of time to let their roots establish before going fully into winter dormancy. For example, in my zone 6b Michigan home, September is the perfect time of year to divide and propagate spring and summer bloomers.

Do you need to divide perennials in the fall? The short answer is no, but you might want to. The benefits of plant division are many. You get more plants, reduce fungal disease, and improve airflow and the root vigor of your plants. The University of Minnesota Extension put out this invaluable guide that briefly describes over 125 common perennials, how often and when to divide them, and any notes about the process. Check this chart or ask your local extension office if they have something similar for common perennials in your area.

How to Protect Perennials Through Winter

Even though your perennials are going dormant, it is still a good idea to do a few simple things now to protect them from the hard frosts of winter. A 6-8 inch layer of mulch can go a long way to protect roots and crowns. Just be sure not to put the mulch on too early, as it can slow the plants from going into dormancy. Typically, after the first hard frost is the perfect time. Then, remove it as early as possible in the spring, as soon as the top layer of soil thaws.

It is important not to protect most perennials too much (like with styrofoam domes), as this can cause premature warming and consequently cause the plants to be even more susceptible to frost damage. In very cold climates, choosing perennials that are proven to do well in your zone is critical. Just because someone says it is perennial doesn’t mean it will come back in your zone! However, even frost-hardy perennials can benefit from the mulch layer described above, especially when establishing in the first couple of years.

Pruning for Pollinators and Wildlife Habitat

If you’re concerned about encouraging pollinators and promoting wildlife habitats, it is important to know which perennials to leave so that birds and insects have the resources they need (food or a home) to last the winter. Native plants can play host to a myriad of beneficial insects in the winter and shouldn’t be pruned back until the spring. Check out the U.S. Fish and Wildlife Service website on winterizing pollinator gardens for more information. In a nutshell, sometimes the less we do, the more we allow the ecosystem to do what it does best!

How Fall Care Reduces Pests and Diseases

Properly maintaining your perennials in the fall is proven to reduce pest and disease pressures on a variety of plant species and in the garden overall. For example, Hostas are often recommended to be cut back in the fall so their leaves don’t harbor harmful slugs throughout the winter that could be detrimental in the spring and summer. Furthermore, if plants such as peonies are afflicted with powdery mildew and aren’t cut back and destroyed properly, the powdery mildew will easily return next year, as it will lie dormant in the old foliage and soil and never entirely go away.

Another classic culprit that can be prevented with fall maintenance is voles. If voles are a problem in your area, one effective way to reduce their presence is by removing their hiding places. Voles love to hide in wood piles, old garden waste, and similar structures. Keeping your perennial plants well-maintained this fall will reduce the chances of voles being present next year.

What Common Mistakes Do Gardeners Make with Fall Perennial Care?

Now, before you get chop-happy, there are a few things to keep in mind. A common mistake in fall perennial care is cutting back everything too soon. It is beneficial to maintain a mental or physical list of all the plants in your yard, noting if they require cutting back or division in the spring or fall. Furthermore, even if they are best pruned in the fall, let them die back naturally first. This might cause a few days of a less attractive landscape, but it allows the plants to gather as much energy as possible before going dormant. Therefore, making their spring debut even more majestic.

As I briefly mentioned under the section about tools, sanitization of tools is critical. Yet, it is often overlooked. Sanitizing your tools properly reduces the spread of diseases from plant to plant and from one year to the next. And, it is easy! Simply spray with 70% isopropyl alcohol and wipe clean. Then, they are ready to use again.

Another common mistake I must mention is over-mulching. While a healthy layer of mulch can be essential for protecting particular species from the hard frosts of winter, putting too much mulch or other protective measures can increase the chances of them getting hurt by frost when the protection is removed. Additionally, you can smother the crowns of perennials, preventing them from receiving the critical airflow and light they need to bloom in the spring. If too much mulch is applied, the plant will essentially think that it got buried under too much soil and won’t resurface propperly in the spring.

How Fall Care Sets the Stage for Spring Blooms

Properly maintaining your perennials each fall is an essential way that you can set the stage for improved spring blooming. Removing dead foliage reduces stress on plants during dormancy and boosts root development, thereby enabling the plant to produce more blooms in the spring.

Additionally, taking care of as much perennial care as possible in the fall means that you won’t forget or get too busy to do it in the spring. Pruning back plants too late in the spring can significantly negatively impact the blooming power of many plants. All in all, cutting back spring and summer bloomers in the fall is a great way to give them a little nudge into dormancy and conserve the rest of their energy for the following year.

Perennial Winter Prep Tips for a Healthy Garden

Pruning back spring and summer blooming perennials in the fall is incredibly important for maintaining overall garden health and wellness. One of the keys to a vibrant garden is proper fall maintenance and winter prep, especially in areas with harsher winters. Whether you’re hoping for a better herb harvest, a bigger spring bloom show, or just to have a well-maintained yard, fall perennial care is a great way to reach your goals. So, don’t wait! Learn what plants you have and what kind of care they need. You will benefit your garden next year by doing a few simple tasks right now.

Lara Wadsworth, True Leaf Market Writer

I am a native of Southwestern Michigan, where I currently reside. I love all things plants! After completing a Bachelor's Degree in Horticulture, I found a dream work-from-home job that allows me to share my passion. Now, I spend my days writing for TLM, playing with my dog, eating delicious food with my husband, and plotting my next landscape or gardening move. I believe everyone should get down and dirty in the soil now and then. Happy Gardening!