Can You Use Whole Leaves as a Mulch?

You might want to use whole leaf mulch between garden beds, but probably not in the beds themselves. Photo:

Question: I notice that in your blog, you often recommend using a mulch of shredded leaves. I have plenty of dead leaves, but they’re not shredded. Would they still make good mulch?

Isabelle Allard

Answer: Yes and no.

Small leaves (those of birches, willows, elms, etc.) make a very good mulch even without shredding, as they form a fairly light and fluffy layer that allows plenty of air circulation, just what you’d want in a mulch.

The problem is mainly with large leaves (like those of maples, oaks, planes, etc.). These leaves sometimes seem settle flat one on top of the other, even interlocking. This creates a barrier that makes it difficult for garden plants to sprout through in spring. Also, this same dense accumulation also reduces air and water circulation, notably reducing the air circulation to the roots of plants: never a good thing. It also reduces the efficiency of soil microbes, the ones that enrich the soil by decomposing fallen leaves. 

A whole leaf mulch can sometimes be the opposite of a good mulch: heavy and dense rather than light and airy.

Also, oak leaves, especially, contain a lot of tannins, phenolic substances which can seriously reduce decomposition. If you chop them into tiny pieces, though, the tannins are quickly leached out.

Soooo, if you want to use whole leaves as mulch, you can, but if you see your mulch is packing down in places, do break it up with a hoe or rake.

So Easy to Shred

String trimmers make great shredders! Ill. Claire Tourigny, from the book Les 1500 trucs du jardinier paresseux

On the other hand, it seems to me that shredding leaves before using them as mulch would not be that complicated. You can chop them up simply by running over them with a lawn mower or put them in a trash can and chop them with a string trimmer.

It’s up to you, but I think you’ll have better results if you shred the leaves before using them as mulch … or even putting them in the compost.

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

3 comments on “Can You Use Whole Leaves as a Mulch?

  1. Silver maple and box elder leaves decompose so readily that it does not mater much. Silver maple crinkles up nicely too. I used them straight. Yucca and palm fronds actually get recycled in greenwaste rather than composted. They just take too long. At work, we are not even allowed to dump Yucca or palm fronds into the greenwaste. (There are no Yucca or palms there anyway.)

  2. Crystal Allard

    Thanks for the info! I was just gifted 7 bags of shredded leaves that had been sitting since last fall and I was hoping to use them as mulch in my veg garden Instead of buying bags and bags of the wood chips I usually buy.

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