The insect-repellent properties of Artemisia and other aromatic plants

Marina Bistrin is an avid gardener from Macleod. Here she discusses the insect-repellent properties of Artemisia and other aromatic plants.

I’ve been wondering what use I can put my Artemisia prunings to. I have to cut down the bush hard every year. So far I’ve given bunches away for use in chicken coops to hopefully deter mites. But I have more to cut. I doubt if my compost worms would enjoy it, so I am looking for other uses for the aromatic and bitter foliage. I don’t know exactly what my species of Artemisia is, but it is quite common in gardens – often poking out over front fences – and I think it is either southernwood (Artemisia abronatum) or wormwood (Artemisia absinthium).

Coincidentally, I have been reading the late, great Juliette De Bairacli Levy’s herbal book entitled The Illustrated Herbal Handbook for Everyone, published which has a chapter largely devoted to deterring pests for the garden. She mentioned using dried powdered southernwood (Artemisia abronatum) and similar aromatic and bitter plants to deter pests. She used to put this powder directly onto seeds before she covered them up with

soil, and sprinkled around young plants that she wanted to protect in their early growth. She wrote that it deterred rats and birds as well.

The other plants she mentioned for this use were rue, pyrethrum daisy, dried and powdered garlic roots, cayenne pepper powder, derris root powder, tobacco powder, wood ash and powdered charcoal. I think that feverfew, which is related to pyrethrum, would also be great for this.

Rosemary and sage are sometimes planted with vegetables and grapevines to deter pests. In Yemen, basil (habba) has been used as insecticide. Tomato haulm (i.e. stems), after the fruit has been gathered, can be hung in trees to deter pests and Mexican Indians apparently used to hang it in their houses to deter cockroaches and poisonous insects.

In this video, Juliette said that she always plants southernwood and rosemary wherever she lives.

Regarding physical barriers to pests, she says that bracken is better under strawberries than straw, as it is rougher, so slugs and snails don’t like to crawl over it. She also used to cut prickly plants when green (because the younger thorns are closer together than the adult plants, and make a more effective barrier), and put these around the base of fruit trees to stop grubs and caterpillars crawling up in the Spring.

She also advocated using mustard family plants as green manures to kill organisms and their eggs in the soil that are harmful to plants.