How to limit damage from slugs |
Jessica Walliser, Columnist

How to limit damage from slugs

Jessica Walliser
Jessica Walliser | for the Tribune-Review
Verbena is a great slug-resistant annual for summer plantings.

Question: Something is eating the leaves of many of my flowers, including my zinnias, hostas, dahlias and petunias. I don’t see any Japanese beetles or other bugs on them, but there are holes in the leaves or the leaves are eaten in from the sides. Do you know what might be happening?

Answer: With such a wet growing season, it wouldn’t surprise me if slugs were the culprit. The plants you name are all on their list of favorites, and unless you’re willing to visit your garden at night, you’ll seldom see the slugs damaging your plants.

Slugs are a huge problem for Pennsylvania gardeners, especially during prolonged periods of wet weather. The damage they leave behind consists of ragged holes in the leaves or skeletonized foliage. I’m willing to bet that if you head out to the garden at night with a flashlight, you’ll find them in action, nibbling away on your plants.

There are several things you can do to limit slug populations. The first is to space plants properly, giving each one enough room to quickly dry off after rainfall. Slugs love wet, so when you water your garden, try to target the water applications at the soil level to keep the foliage dry. I know this isn’t possible when your irrigation comes from Mother Nature, but if you water by hand during dry spells, water the roots of the plant only.

Second, handpicking slugs can be quite effective. In the evenings, pluck the slugs from your plants, dropping them into a jar of soapy water.

There are also many types of commercial and homemade slug traps you can use to lure the slimy buggers to their death. Beer is often recommended as a lure for these kinds of traps, but personally, I can’t stand emptying the trap when it’s full (gross!), so I skip traps and turn to organic slug baits instead.

Organic slug baits are based on the active ingredient iron phosphate. Iron phosphate-based baits are scattered around susceptible plants where they’re discovered and ingested by slugs. Though the slugs don’t die instantly, they do stop feeding immediately and die soon after.

Chemical-based slug baits should be avoided as they can also harm pets and wildlife, though many brands now include a distasteful ingredient to help prevent accidental ingestion.

There are other slug-deterring products on the market as well, including wool pellets, slug collars and copper tape, all of which have varying degrees of effectiveness depending on how and where they’re used.

And, of course, you should always plan to include many species of plants not preferred by slugs in your garden each season. Plants with highly scented foliage (such as salvias, artemisias, lavender and Russian sage) and plants with fine fuzz or hair on their foliage (such as Brunnera, dusty miller, verbena and Verbasicum) are the best bets.

Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio with Doug Oster. She is the author of several gardening books, including “Attracting Beneficial Bugs to Your Garden,” “Good Bug, Bad Bug,” and her newest title, “Container Gardening Complete.” Her website is Send your gardening or landscaping questions to [email protected] or The Good Earth, 622 Cabin Hill Drive, Greensburg, PA 15601.

TribLIVE commenting policy

You are solely responsible for your comments and by using you agree to our Terms of Service.

We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.

While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.

We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers

We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.

We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.

We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.

We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.