Wormwood As Insect Repellent
Answered by: Conrad Richter
Question from: Jeanne
Posted on: May 16, 1998

I read that wormwood plants repel cabbage butterflies, so planting cabbage family around wormwood protects from these insect pests. I also read that dried wormwood keeps moths out of woolens. Do you know whether this is true, and if so, is it true for Artemisia pontica, or only Artemisia absinthium? I found Artemisia pontica in the local garden shop, but haven’t located Artemisia absinthium. Do you sell this as seeds?

Helen Philbrick and Richard B. Gregg wrote in their seminal book, "Companion Plants" (Stuart and Watkins, London, 1966), that wormwood does repel moths and will protect cabbage plants from cabbage butterflies. We have not tried it for this purpose so we cannot say from experience that it does work.

In general, the traditional methods of companion planting have been difficult to verify in modern, controlled experiments. However, in the case of wormwood there is a history of broad repellent and insecticidal use that is self-consistent and rational based on what is known about the chemical constituents and the medicinal properties of the plant. We would not be surprised that wormwood does indeed repel cabbage butterflies. The effect is, however, unlikely to be total; additional interventions may be necessary to keep cabbage butterflies down to manageable populations.

There are many types of wormwood but most of the literature on wormwood’s medicinal, insecticidal, and insect repelling properties relates to Artemisia absinthium, the common wormwood. Other species, such as the roman wormwood (Artemisia pontica), are likely to have similar properties in general, but little or no research has been done to verify that assumption.

According to James Duke’s "Handbook of Medicinal Plants" (CRC Press, Boca Raton, FL, 1985) essential oil of common wormwood is known to have repellent properties. Twigs of dried wormwood are traditionally used as a moth repellent. It was once used to repel weevils in granaries and was strewn on the floor and stuffed into pillows for cats and dogs to repel fleas. Fresh branches are placed to repel mosquitoes.

Medicinally, wormwood has been used to expel worms in animals and humans, but is now considered too dangerous for this purpose.

Philbrick and Gregg write that gardeners have long noted that plants growing close to wormwood do not thrive. Apparently, experiments in the 1940s showed that the growth of anise, fennel, sage, and caraway was inhibited by toxic root excretions from wormwood. The effect is apparently especially strong in years of heavy rainfall, and it persists for a period of time.

They go on to say that wormwood tea sprayed in the fall and spring will discourage slugs. They suggest a wormwood bath to rid cats and dogs of fleas. They say that wormwood tea can be used as a spray to combat aphids but should not be used too often on tender plants or it will retard their growth. They also say that an extract of wormwood and tomato foliage together will repel flies.

Richters carries seeds and plants of common wormwood (A. absinthium), as well as seeds or plants of a dozen other related wormwoods.

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