Some common garden plants might help keep bugs away | TribLIVE.com
More Lifestyles

Some common garden plants might help keep bugs away

Associated Press
1506354_web1_1506354-9882fd2b1fcb4d2896cf218151326593
Associated Press
This lavender shrub is among the herbs and ornamental flowers scientifically proven to naturally deter troublesome insects but biochemists generally don’t believe they’re very effective.
1506354_web1_1506354-289ad511d7154bbb8d0afb3c27cc516e
Associated Press
Plant-derived insect repellents, like this rosemary shrub, contain volatile compounds that work but quickly exhaust themselves, unlike the DEET-based synthetic chemicals that don’t have to be reapplied every few hours. Natural insect repellents are believed by many people to work although they’re not as effective as the synthetics.

If mosquitoes, gnats, black flies and no-see-ums are driving you buggy, then consider cozying up to some lavender, marigolds or basil. Scientists question their overall effectiveness, but many fragrant ornamental flowers and herbs grown around the home have properties that can repel insects.

Insect repellents are divided into two primary chemical classes: natural and synthetic. How effective they are depends on the targeted insects and the host plants’ essential oils.

“Plant-derived insect repellents are very volatile compounds that work but exhaust themselves very quickly,” said Walter Leal, a biochemist and distinguished professor at the University of California, Davis. “They’re good, but they should last for a longer time.”

The most frequently cited plant-based repellents include the oil of lemon eucalyptus (OLE) and oil of citronella.

DEET (N,N-Diethyl-meta-toluamide), on the other hand, is a strong synthetic repellent considered the yardstick for protection from insects, but often is confused with DDT, the insecticide blamed for so many environmental problems, Leal said.

“DEET is not an insecticide, and it’s a chemical of low volatility so it lasts longer,” Leal said. “People are not interested in reapplying something every few hours.”

If you do plan to try natural repellents, then the top herbs for which there is scientific evidence of mosquito deterrence are lemongrass, lemon balm, bee balm and lemon thyme, said Gary Bachman, an Extension horticulturist with Mississippi State University. Rosemary, lavender, basil, mint, citronella and catnip also may help discourage insect pests, he said.

Ornamental flowers believed to be effective at deterring troublesome bugs include marigolds, alliums, chrysanthemums, petunias and geraniums.

Be careful with skin contact

There are “a lot of plants that if you rub against them release vital oils,” Bachman said. “I think that’s probably of some benefit in repelling insects. But if you just have those plants sitting in a pot, I don’t think there’s much chance of keeping troublesome insects away. You have to put some effort into it, like rubbing crushed plant material onto your clothing or skin.”

Bachman cautions, however, that some of the volatile oils produced by those plants could be irritating.

Most insect repellents designed for use on the skin must be registered by the U.S. Environmental Protection Agency before they can be sold in stores. EPA registration means the repellent has been tested and approved for human safety and is effective when used according to label directions.

Synthesized OLE is an effective insect deterrent although “pure” oil of eucalyptus is not recommended. “It has not undergone validated testing for safety and effectiveness and is not registered with EPA as an insect repellent,” the Centers for Disease Control says.

Does that mean ornamental plants and herbs containing natural insect repellents are practical additions for residential settings?

“Botanical repellents are a nice idea, but I don’t think they’re the best solution for discouraging insects,” Bachman said.

TribLIVE commenting policy

You are solely responsible for your comments and by using TribLive.com 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.