6 Reasons You Shouldn’t Cut Back Flowers In Autumn

Traditionally, one of the last outdoor chores for a homeowner to do in fall before snowy winters set in is to perform a fall clean up on their garden and flower beds. The common practice of trimming all perennials down to the ground may look nice, but it also removes much habitat that can be utilized by native bees and other beneficial insects as well as eliminating food & cover for birds. So, perhaps you can read on and hear me out for not completely clear-cutting your flowerbeds come October!

I’m going to give you 6 reasons to not cut down your flowerbeds to the ground, or at least modify your methods to benefit some of your local wildlife. This is one of the biggest changes you can make to the way you garden that isn’t often considered, and has a huge impact on your local ecosystem.

1 – Food for birds

The seed heads on top of your dormant flowers are one of the best sources of food for birds in Winter. Removing those seed heads as part of a fall clean up robs backyard birds of an excellent source of nutrition and calories they depend on during the Winter.

Some of the easiest native flowers to grow that will act as natural bird feeders include Asters, Coneflowers, and Sunflowers of all kinds. [1] Each year I get surprised by just how many seeds birds clean from my plants. Even plants I didn’t know they could perch on tend to get cleaned off. Just last Winter I went to collect some seed from Verbena hastata and was surprised to find it completely cleaned off!

What is interesting, and you will likely observe it too, is that they seem to have preferred foods. For instance, any kind of Sunflower, whether annual or perennial seem to get eaten first. In fact, they will go after seeds while they are still forming! Later on they visit other species, Monarda, Liatris, and eventually even less preferred species such as Verbena. So it appears that birds have taste preferences!

2 – Let plants spread

If you leave your seed heads up, and the birds eat the seed…..you know all that seed the birds are eating? Well, some of it is going to be spread via bird droppings. It is true that some seed will be completely digested, but others will pass through and germinate when Spring arrives. Should we be lucky this will happen in a wild area like a powerline cut or ditch. Thus you may encourage the spread of the native species via bird droppings, thereby creating more food for pollinators and improving your environment.

I have ‘mystery’ Echinacea that sprouted up in parts of my yard that are far away from any parent plant. Furthermore I have a healthy population of Sawtooth Sunflower that I have never planted. While many seeds may be digested, some pass through in-tact enough for Spring germination.

3 – Give bee larvae a place to overwinter

While some people may find dead flower stalks unsightly, know that many insects like to burrow into them to overwinter. Leaf-cutter bees, mason bees, and others all utilize hollow plant stems for nesting. Their larvae will over-winter for two seasons before emerging. [2][3] Thus, if we are are to help them survive and reproduce, we should be leaving at least a portion of plant stems above ground of six inches or more.

It doesn’t take many plants standing to make a large difference. Research has shown just how resilant nature can be in the face of human involvement, even in cities. [4] Cavity nesters have been found to utilize manmade holes from small pipes or building features to nest in. And while making a bee hotel is a fun project and provides lots of interest, it isn’t as easy as leaving last year’s stalks standing 12″ tall.

Joe-Pye Weed, Bee Balm, Bergamot, Mountain Mints, and any other species with a hollow stem can be left upright. Even leaving a portion above ground and never cutting it back can make it possible for these baby bees to survive and eventually take flight.[5] [6]

In our front flower beds, we generally leave most of the stalks up all Winter, and in Spring will only cut back a portion, as with most of these plants the new stalks grow up quite quickly.

4 – Giving cover to wildlife

The more foliage that is left up, including large perennials and tall grasses like Little Bluestem, the more cover will be available for birds and other wildlife. This can especially help with birds that like to feed on the ground during Winter such as Dark-eyed Juncos, Carolina and House Wrens, and White-throated Sparrows.

Each fall I get to see numerous small birds and chickadees feast on seed that fell to the ground from Asters, Blue Vervain, and Liatris. It really can provide interest if you enjoy watching birds or wildlife. Rather than having static, dead patches of mulch or snow you can be treated to all the life that the birds will bring to your yard.

5 – Leave the leaves for overwintering butterflies!

Although we may have a desire to rake up all of our leaves in Fall, we should consider leaving as many as we can! This is because some insect pupae will overwinter wrapped up in leaves. Butterflies such as the Baltimore Checkerspot, some Swallowtails and others will hide in leaf litter. [7][8]

But when it comes to leaves that fall in my yard, I almost never rake anything up unless I think it may smother out my grass. I find that the wind distributes most of the leaves thinly enough so that my grass will survive. And thus I don’t need to do anything to keep my grass alive nor any pollinators that may be overwintering inside them.

I know my situation doesn’t apply to everyone, and nor would I want bare patches in my lawn from leaf-litter. But removing a ‘grass-killing’ mat of leaves from under a Maple or Oak tree doesn’t mean we have to remove every leaf from our yard or remove leaves from our flower beds.

Finally, this doesn’t mean you can’t ‘use’ Autumn leaves though. I pick them up from the street (bagged & thrown out by others), get them from my neighbors who do rake to use as a thick leaf mulch in my vegetable garden (you should be doing this too!). These leaves would be thrown in a landfill, and I’m just stopping that process by putting them in my garden to improve my soil. I’ve personally found leaf mulch to be an excellent way to naturally add nutrients to my soil.

6 – Provide Winter beauty for your garden

Leaving seed heads an stalks up in Fall may sound messy, but many species can be quite beautiful. Snow that gathering on Echinacea seed heads look almost like cotton balls, Ironweed can look great standing tall in Winter, and all of these will also help provide cover and food!

Final thoughts

Changing how we as gardeners approach Fall Clean-up is a journey. Your Winter flower beds may look a lot different, but you will grow to love them as you observe all the wildlife that make use of them. Furthermore, you will feel better knowing that by not clearcutting plants to the ground we are also helping local beneficial insects.

We all get started in native plants not just for their beauty or wildlife they attract, but also out of our desire to do something right for the environment in our own backyards. Reducing the amount of fall clean up can directly impact your local wildlife in a positive manner.

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