WINTERTHUR, Del. — I am trying to be smug when I tell the garden honchos at Winterthur, the du Pont estate north of Wilmington, that instead of blowing and bagging leaves, I just pick them up with the lawn mower.
The bag fills, I push the mower up the hill to the far corner of the yard and just pile the stuff on the compost heap. The leaves turn to black gold, my carbon footprint is reduced and the landfills are spared.
Carol Long and Chris Strand shoot me the sort of look that says: Are you crazy? For more than 20 years, the gardeners at this expansive and famously leafy estate have been mowing the lawns with mulching mowers. The machines inhale the leaves, chop them into shreds and deposit them as the mower moves along. Engine noise is confined to the muted chug of the mower, not the incessant high-pitched whine of the leaf blower.
And there are no bags to unhook and drag anywhere, just a confetti-like litter left on the grass. Ripped into small pieces, the flakes melt away quickly as microbes and worms do their work of enriching the soil. The thicker litter in the woodland beds is more slowly consumed but is gone by spring.
It is such a simple system that Strand, garden director, and Long, assistant garden curator, wonder why it hasn’t caught on. They are certainly converts in their own gardens. “I spend a fraction of the time I used to spend raking and transporting leaves,” says Strand.
Mulch mowing won’t interest the person who craves noise or needs to blow every wayward leaf from his manicured lawns, but for the rest of us, it seems like a pretty good way to deal with the effects of nature and gravity.
When H.F. du Pont lived here, he had an army of 90 gardeners hand-raking the leaves. The woodlands generate about 500 tons of leaves a year, says Strand. Now, as a public museum and garden, Winterthur relies on a gardening team of 16 and has come to count on this highly efficient approach to the leaf drop.
Kevin Stouts, one of Winterthur’s mower meisters, uses a commercial 48-inch riding mower and a simple 20-inch push mower. Mulching mowers are designed for finely chopping grass blades so they will break down quickly in the lawn. Even nonmulching mowers will do the job, Stouts says, just remove the bag and close the discharge chute.
With lawns, frequent mowing is best to avoid leaf loads that may slow the mower’s progress. Just as you should mow the lawn every three or four days in the frenetic growth of a wet spring, a twice-weekly leaf mow in the fall will stop things from getting out of hand.
The mower seems most efficient when reversing, says Stouts. “There’s a lot of back and forth activity to get that real clean look,” he says.
In Winterthur’s woodland area, the approach is a little different. The terrain gets two mows in the fall. The gardeners wait until about half the leaves have dropped before making the first cut. This also takes care of the dying top growth of hostas, ferns, wood asters and other perennials.
All that mowing equipment and human traffic apparently doesn’t harm the crown buds from which next year’s growth will come. The bulbs start appearing in January, and by May the hostas and ferns are back as robust as ever.
In early December, after all the leaves have dropped, the mowers go through a second time.
Strand says he has noticed “a lot more earthworm activity when you do mulch mowing.” Returning organic matter to the soil is one of the basic tasks of the organic gardener.
Adrian Higgins is the gardening editor at The Washington Post.
