Fall leaf raking seems like such a straightforward task — rake the leaves, stuff a few down the back of someone's shirt, get chased around the garden and end up dirty and sweating with a large pile to take to the green waste or the compost bin. Fun and done, right? But every year I struggle with the question of whether raking is doing more harm than good.
Leaf litter is actually pretty great stuff: It protects plant roots from frost, keeps weeds down over the winter and contributes to the soil as it breaks down. Even better are the wildlife benefits; salamanders, butterfly larvae and native insects all overwinter in leaf litter. Those native insects are great news for anybody hoping to attract birds to the garden, as birds need that source of nutrition throughout winter and spring to survive and feed their young.
Unfortunately, all those benefits come with their downsides: not only do good bugs overwinter in fall leaves, but snails, slugs and other garden pests do, too. Plus, a thick mat of leaves can rot perennials and shade out areas of lawn. I hate to even mention this last part — but after running a landscape maintenance business for over 15 years, I'll admit I've developed a bit of a neatness fetish. By December, all of that brown leaf litter fluffing about just looks messy to me.
Raking is a surprisingly divisive topic. Most gardeners I talk to fall into one of two camps: rake everything to a state of sterile perfection, or leave everything in a wild messy jumble and let it take care of itself. Over the years I've developed a more subtle approach that seems to provide the best of both worlds. There's nothing I love more than seeing salamanders, interesting bugs and birds rustle about in the garden — it's the ultimate in winter interest. Yet I'm totally unwilling to have that $24 perennial I special-ordered smothered by thick maple leaves, and as an organic gardener I'd rather prevent pest problems than treat them later. So here's how I approach the fall bounty of leaves.
Anything that gets pests or diseases. Rose bushes and fruit trees are the worst offenders, since they suffer from such a wide variety of pests and fungus, so rake up any fallen leaves or leftover fruit. I also rake both petals and leaves from under rhododendrons and camellias. Fungus and thrips can overwinter in the curled, leathery leaves of rhodies, and camellias suffer from petal blight, a disease that attacks those ruffly old-fashioned camellias and turns the flowers brown and clumpy. It's best not to even compost these leaves, either. I just take them to the green waste to make sure I'm not spreading disease issues around the garden.
Finely mulched beds. I'm a sucker for the beautiful fine texture of that micro-mini fir bark they sell at the nursery, and I often use it to topdress garden beds to prevent weeds. Unfortunately, the smaller the mulch, the more easily it breaks down into a lovely composty soil, especially when covered with a layer of damp leaves all winter long. If you don't want to be buying more mulch every spring, rake up those leaves.
Beds with landscaping fabric. I'm certainly no fan of landscaping fabric, but where it is used, you may as well avoid messing it up. Allowing a layer of delicious leafy compost to form on top of it is kind of counter-productive. However, all is not lost. In beds where you have to rake, either spread those extra leaves in the back of the garden, layer them in your vegetable beds lasagna-gardening style, or put them into the compost bin.
Anywhere unmulched. If your garden beds don't have a layer of fine woodchips or shredded bark holding down the weeds, you'll find all those dropped leaves a huge benefit, particularly in beds that primarily have shrubs and trees. The fall color is gorgeous to look at while it lasts, the leaves prevent those beating Humboldt rains from causing compaction of the soil surface, and come spring you'll find your soil is soft, rich and plantable.
Any place with large bark. If your woodchips are on the medium to large side of things, a layer of leaves will have very little effect on their longevity, as long as you rake them up come late spring. By leaving them throughout the winter, some of that leaf compost will filter down into your soil and enrich it, and you'll get all of the wildlife benefits that come from allowing the birds, salamanders, frogs and insects to find food and shelter in that leaf layer.
The back of beds. Even if you're a neatnik like I am, most of us have areas of the garden that we just don't really look at. Those are prime places to take advantage of the benefits of leaf litter. You can even distribute some of the leaves from elsewhere in your garden to these farther off corners and know you're doing a good thing for both your soil and our local wildlife.
The lawn. While the lawn is the most obvious place people usually rake, we've got it all wrong. Though we shouldn't leave thick mats of maple or sycamore leaves sitting on the lawn to shade out and kill our turf, studies have shown that shredding the leaves and putting them back, even in a thick layer, provides huge soil and nutrient benefits to the lawn with very little drawback. By shredding leaves first, you make sure that a little bit of light and air can get through to keep the grass alive. Don't have a shredder? No problem. Just run over the leaves with your mower a few times to chop them up.
Perennial beds. Here's another place where aeration makes all the difference. Though a heavy layer of leaves can collect water and form an impenetrable barrier on top of delicate perennials, rotting their crowns, shredding the leaves once again allows the garden to benefit from the leaf litter without any discernible drawback. If you are worried about slugs and snails overwintering, just pick up a little bit of that organic Sluggo stuff made of iron phosphate and sprinkle it around the garden as your perennials begin to emerge. If you don't want to go through the trouble of raking, shredding and redistributing, some people allow the leaves to sit on their perennial beds and just fluff them with a garden fork in midwinter to allow their perennials to breathe and spring bulbs to pop through.
If you're going to rake this fall, consider investing in a rubber rake, like the one from Clarington Forge. You can run it over perennials and shorter ornamental grasses without tearing up their foliage, which makes raking perennial beds so much less of a production. And best of all, when used on pavement it eliminates that horrible SCREEE- SCREEE sound from old-fashioned metal ones (and it's quieter than plastic rakes, too). Your neighbors will be delighted you didn't send them running for the Advil again this year.
Genevieve Schmidt is a landscape designer and owns a fine landscape maintenance company in Arcata. She blogs over at www.NorthCoastGardening.com.