Falling Leaves

As of yesterday’s rain, almost every leaf has fallen off the trees -is it a coincidence that I felt myself looking forward to spring this morning?  I really miss the leaves when they are gone, so I try to remind myself: the leaves are not really gone, they are simply on the ground.  

For years gardeners have gotten advice about “fall clean-up.” That they should cut back dried plants, rake up leaves, maybe use leaf blowing machines, put leaves in bags to be carried away -all in the name of tidiness (oof -so much work!).

But, more and more, gardeners interested in supporting birds and butterflies and pollinators are discovering an ancient truth: it’s better if they don’t do all this stuff.  Dried plants and leaves on the ground are actually important winter habitat for a variety of struggling insect populations: fireflies, bumblebees, solitary bees, butterflies, and moths.

The New Fall Do-Nothing Advice

“When nothing is done, nothing is left undone.”

Tao Te Ching, Stephen Mitchell translation

It cracks me up just how Taoist new gardening recommendations are.  The advice for a nature garden these days is more like: It’s fall now.  Don’t worry about it.  Definitely don’t do anything about it.  Maybe put your hoses away.

1. Leave the dried plant stalks.

• It’s prettier this way, with the brown, dried seed heads.
  
• The birds like/need to perch and eat the seeds. 
  
• With native plants, there are often little insects (including solitary bees) sleeping the winter away in the stems, so definitely don’t compost them now.   
  
• It’s recommended to wait until early march to cut plants back, leaving the bottom two feet of the stem intact to provide habitat for a new year of stem-nesting solitary bees

These days, some garden designers really think of “winter interest” first, when choosing plants.  Winter interest includes things like the form and colors of dried grasses, choosing plants with seed heads that will be long-lasting, choosing trees and bushes with interesting bark, and arranging plants with winter in mind.  For example, placing dark seed heads in front of a lighter dried grass for contrast.  The new interest in garden design for winter is definitely a good thing, considering the garden is in its winter form for at least 5 months in the midwest and that many little insects really need these plants left in place for shelter. 

2. Leave as many leaves in your yard as you can manage. 

There are a number of great ways to do this and simultaneously build your garden.  

•  Letting leaves just lie where they fall, and not chopping them up with the mower (that’s what I do, or not-do). When leaves are chopped up, cocoons, caterpillars, and eggs are also chopped up. Additionally, chopped up leaves degrade faster, leaving less available food for the leaf pile food chain in the spring.
• But if you are especially concerned for the welfare of your grass, as some people I know are, then you could find another spot for them in your yard.  Three to four inches of leaves makes a great weed suppressing mulch in existing garden beds, while improving soil as they break down, and a few inches of leaves won’t smother emerging perennials in the spring.  (But a note of caution: a very thick layer of leaves may lead to some smothering).
• If there is a mature tree in your yard where you find you are always raking away the leaves to save the grass, well, you could consider turning the area under the tree into a perennial bed that the tree will simply mulch for you. 
• In any spot you want, you can use a thick layer of your leaves to create garden beds, smother grass, and shelter many wonderful insects.  Creating a new garden bed, along a fence line, next to the deck, etc.  is a great use for leaves.  Sprinkling some wood chips on top will help keep them in place over winter.   

For the Love of Fireflies

About 5 years ago, I started doing nothing with the leaves.  The primary reason was because I was trying to encourage fireflies in my backyard, and after a little research, it seemed like that “leaving the leaves” was a top suggestion for firefly conservation.  The leaves feed the slugs, snails, and worms that are the main food for firefly larvae (not to mention countless millipedes, roly-polies, spiders, mites, and billions of soil organisms that depend on fallen leaves). 

Now it may have been a coincidence, but the summer after we left our leaves (and did not mow them), we had an amazing summer of fireflies.  As far as I could tell, we went from sparse fireflies, to the craziest number of fireflies I’d ever seen.  Now was it all down to leaving the leaves?  Probably not entirely, but no doubt all those fireflies did benefit from the extra snails and slugs, who had benefited from the leaves.  And as you can imagine, from then on, I have left the leaves.  

What’s good for the fireflies is good for the other guys

Bumblebee queens often overwinter in little burrows a couple inches underground, and it’s thought a thick layer of leaves can provide extra protection from some of the harshest winter weather.  

Butterflies and moths use leaves for overwintering habitat for different life stages. 

• Caterpillars: The great spangled fritillary, woolly bear caterpillars (aka Isabella tiger moths), tawny emperor butterflies, and Baltimore checkerspots all wrap themselves in leaves and spend the winter in leaf litter
• Eggs: Red-banded hairstreaks on lay eggs on fallen oak leaves which become the first food of their caterpillars.
• Cocoons: Luna moths disguise their cocoons as dried leaves to blend in to leaf litter.

There are so many good, beautiful, and fun reasons to not rake up your leaves (almost nothing is more fun for little kids than catching plump toads and fireflies). So give yourself a break this year and all the years to come. Just watch the leaves fall and don’t do a thing about it.

Have any other non-rakers out there seen the benefits of doing nothing? Let me know!

Resources:

Leave the leaves!, Xerces Society

Fall cleanup with ecology in mind, with Doug Tallamy, A Way to Garden, by Margaret Roach

Firefly.org, Conservation and Research

Wildlife Connections: Leaf Habitat, University of Kentucky

Bewitching Butterflies and Moths with Fall and Winter Habitat, Maryland Department of Natural Resources

Brown Gold: The Gift of Fall Leaves, Backyards for Nature, Valley Forge Audubon Society