Why Are There Snails in My Garden?

(Photo courtesy of Chris Bernstein)

I’ll never forget the first time I spotted a garden snail in my yard. I was dumbfounded. Like most people who grew up on the coast, I’d seen plenty of snails in tide pools and at the beach. But I didn’t understand how one could be crawling up the side of my trash shed, first thing in the morning.

“Aren’t snails supposed to be marine animals?” I wondered. “Had this one escaped from the French restaurant in Scituate Harbor? Was it an escargot on the run?”

Later that season I found a snail in a particularly weedy section of my tomato patch, and another crawling up my front walk on a rainy day. After some investigation online, I learned that there is more than one variety of snail.

Snails are mollusks. Most mollusks live in the water, especially the ocean, but some have adapted to living on land. The Brown Garden Snail (Helix aspersa) is one of these.

Garden snails are protected by a hard, glossy, spiral shell, which can range in color from yellow to brown. By age two (adulthood), they can grow up to 33 mm in size. Some will live as many as ten or even fifteen years. They move by means of a long, flat, muscular foot, which secretes mucus to help them glide, and often leaves a slimy silver-colored trail in its wake.

Garden snails thrive in moist, relatively quiet environments like my weedy, damp garden – as long as there is adequate food supply. Most are nocturnal, but when it rains or it’s cloudy, some will come out during the day. Garden snails do not like the sun. In dry weather, they curl up into their shells and seal the entrance. In the winter, they hibernate in the ground.

Garden snails feed on live and decaying plants, tree bark and any organic matter they can find in the soil. They especially enjoy the types of plants grown in a typical backyard garden, such as beans, peas, lettuces, carrots and tomatoes, as well as a number of flowers and fruit trees.

Originally identified in Italy by O. F. Müller, garden snails were introduced to the United States via California in 1850 (They were imported in order to provide a domestic source of escargot). Like many non-native species, brown garden snails have adapted well to the California environment and are now regarded as a pest by gardeners and growers, as they loves to snack on crops and ornamental plants. Since many of our vegetables and seedlings are grown in California, snails have been dispersed all over the country via truck and airplane, hitching a ride on our produce and garden plants.

While they can be fascinating to behold, garden snails can cause big problems in the back yard. Ground beetles, snakes, toads, turtles and some birds find garden snails delicious. But if you find that you have more snails in your yard than you care to deal with, there are a number of methods to help you get rid of them.

If garden snails are eating your fruit trees, you can try banding the trees with copper foil. There are some commercially available poisons that will kill garden snails – but make sure that the poison won’t destroy the rest of your garden or the species therein. You can also try releasing predatory Rumina decollata snails.

Some people find that setting out shallow pans of beer will take care of a snail problem. The snails find the beer irresistible, but after they drink, they drown.

Another method is to reduce their habitat. First eliminate places under which garden snails may hide – such as boards, brush and debris. Then create a trap by placing a board on the ground near where the snails have been active. Elevate the board in the corners with a few stones. The snails will congregate there during the night and in the morning, you can remove them. Dropping them in a jar of water mixed with rubbing alcohol should finish the job.

One final way to get rid of garden snails is simply to eat them. In fact, the brown garden snail is considered the second best choice for culinary use, inferior only to the Roman snail, which is larger, lighter in color, and lives in warmer environs. Who knew you could grow your own escargot?

Sources:
www.creatures.ifas.ufl.edu/misc/gastro/brown_garden_snail.htm
www.gardensafari.net/english/snails.htm
www.kiddyhouse.com/Snails/snail.html

By Kezia Bacon-Bernstein, Correspondent
May 2005

Kezia Bacon-Bernstein's articles appear courtesy of the North and South Rivers Watershed Association, a local non-profit organization devoted to the preservation, restoration, maintenance and conservation of the North and South Rivers and their watershed. For membership information and a copy of their latest newsletter, contact NSRWA at (781) 659-8168.