Q: Several years ago, we got rid of our lawn (and more than 50 yards of thick, impenetrable clay soil) and converted our front yard into a combination of woodland and Japanese garden. Because we don't want to block the partial views our neighbors have of Lake Washington, we have only small yard trees, including a 50-plus-year-old Japanese maple and some alpine firs.
We've added two smaller Japanese maples, some vine maples and mountain hemlocks. The rest are mainly heather, junipers, dwarf blueberries and small rhodies, with thyme and blue star creeper as groundcovers.
Our question: Should the leaves from our deciduous trees be cleaned up for winter? We know they provide good mulch, and that argues for leaving them where they fall.
But we also read that they provide protection for slugs and other undesirable pests. And they also seem to suffocate the groundcovers when the leaves pile up around some plants.
A: Leaves that have been chopped up make a great organic mulch. But left whole, even from small trees like yours, leaves pack down into a sodden, heavy mat and keep air from circulating into the soil.
In the forest, where leaves are left where they fall, nature isn't trying to grow a variety of bulbs, groundcovers or other small treasures that suffocate or rot away covered by a blanket of leaves.
Well-chopped or shredded leaves can be spread directly on the garden as mulch, or added to the compost, where they create a nice, light layer of material as well as provide the carbon component needed in good, rich compost.
If you don't own a shredder or don't want to rent one, a lawn mower works well to shred leaves. Spread leaves on the lawn, or leave them where they've fallen, and attach a bagger to your mower before you begin cutting. As you cut the lawn, the leaves will be shredded and gathered into the bagger.
Or you can rake leaves into a pile and run the lawn mower without a bagger through the pile. Direct the discharge chute so the shredded leaves end up in a pile and not blown all over the place.
Valerie Easton also writes about Plant Life in Sunday's Pacific Northwest Magazine. Write to her at P.O. Box 70, Seattle, WA 98111 or e-mail planttalk@seattletimes.com with your questions. Sorry, no personal replies.
