Edition: U.S. / Global

Garden Q. & A.

By Leslie Land
Published: September 25, 1997

Taming Driveway Fungus

Q. For the last several late summers, I've had some white fungus growing through the asphalt of my driveway, breaking it with an astonishing strength. On occasion, a few of these growths, which are about three inches big, pop on the lawn. I dig them out, but the next year they come back. This year two big ones have pushed through already. Do you have an explanation or a cure?

A. Ain't nature grand! All that force from a little fungus. Actually, the fungus is not little; it's a webbing that has, from the sound of it, spread through a good portion of the soil beneath your lawn and driveway. The webbing is called a mycelium. It can live for many years, feeding on buried organic matter. When conditions are right, it produces mushrooms, which are its fruiting bodies. (They aren't fruits, because fungi aren't plants, but it's the same idea.)

The only way to get rid of them is to get rid of the parent fungus. Gary Lincoff, the author of ''The National Audubon Society Field Guide to North American Mushrooms'' (Alfred A. Knopf, 1981), said it is probably Coprinus comatus, commonly known as the shaggy mane. These mushrooms have a bullet shape, almost a point, so they are very well suited to pushing through things, including asphalt. They come up through blacktop so frequently that it's almost as though they had an affinity for the stuff.

Eventually the mushrooms under the driveway will run out of food and stop producing. If you can't wait, you'll have to rip up the asphalt and remove at least a foot of the soil underneath. Replace the soil with a bed of sand or gravel and pour new asphalt. The mycelium grows quite close to the surface and needs organic matter to feed on, so this treatment should discourage it.

A Mysterious Visitor

Q. This summer and last our lawn has been torn apart every night. Large areas of grass are cut almost in a circle, with a hinged area at the rear. This leaves exposed areas of soil. It has been suggested that the marauder may be a skunk, groundhog or chow. The lawn was treated for grubs in early spring. Can you suggest a way to destroy the attraction for the intruder or to repel the animal?

A. If you had a groundhog that confined itself to digging up the lawn, you'd be Lady Luck's own tot. And dogs are daylight destroyers; if a chow were making those holes, you'd see it in action. Your busy visitor is indeed a skunk.

It's tempting to say the creature is digging lots of holes because it can't find grubs and has to keep looking, but the truth is skunks eat earthworms, too. Skunks are attracted to ecologically healthy landscapes, where they have a natural place, so you would not want to remove the attractant.

The only effective repellant is a large dog. Since you don't have one, there are two options: you can call a professional skunk-remover (look in the Yellow Pages under pest control or animal control), or you can just relax and do nothing. Skunks are beautiful and quite shy, disinclined to make trouble unless provoked. They improve the garden environment by eating yellow jackets and wasps -- a skunk will wipe out a whole nest of these pests overnight. Most of their digging is done in late summer and fall and will not do permanent harm to the lawn.

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