Companion Planting: Wormwood or Artemisia
History & Use:
Artemisia has a colorful and rather dubious history: Artemisia was the wife and sister (yes, that is correct) of the Greek/Persian King Mausolous from which we get the word mausoleum. The genus artemisia was named after her and includes over 400 plants. Artemisia was a botanist and medical researcher.
Many of the artemisia varieties have insecticidal properties with wormwood being the most potent. Roman wormwood is less toxic and is used to flavor the drinks Vermouth and Campari. A sachet made of wormwood leaves will keep moths at bay. Did you know that the delectable herb tarragon is of the artemisia genus?
Wormwood, Artemisia Absinthium has been used for centuries as a moth repellant, general pesticide and as a tea/spray to repel slugs and snails. Before its' toxicity was known it was used as the name implies: a worming medicine for people and animals. . Historic references to wormwood go back as far as 1600 B.C. in Egypt. Wormwood leaves contain absinthin a substance which can be toxic to other plants. You may have heard of the alcoholic drink "absinthe" a green colored beverage that is now illegal in most countries. And rightfully so as it has been said that the painter Vincent van Gogh was imbibing of absinthe when he lopped off his ear to send to a woman. The absinthin being water soluble will wash off the leaves and leach into the soil interfering and stunting the growth of plants in close proximity to the wormwood. Because of this do not use wormwood tea as a spray on small plants or seedlings, only on more established plants. We offer only our own experience in using wormwood tea as an insect spray and suggest that you use it with caution until you see how it works for you. For best results spray directly on the target insects or use dried wormwood cuttings spread on the soil in the garden. Don't use wormwood tea on edible plants, use only on ornamental plants. Dried worm wood sprigs may be used in the garden as a scent deterrent. Wormwoods are toxic so must not be ingested.
- To Make Wormwood Tea:
8 ounces wormwood leaves
4 pints of water
1 teaspoon castile soap
Effective against: Aphids, caterpillars, flea beetles and moths.
Putting dried sprigs of wormwood in the garden along side carrots
and onions will mask their scent, confusing insects in particular the
carrot rust fly. The dried wormwood will not have the growth inhibiting
effects of the fresh herb.
1.Simmer wormwood leaves in the water for 30 minutes. Stir, strain, and leave to cool.
2.Add the castille soap to wormwood mixture and use to spray.
- Plant Culture:
Hardy to zone 4 and some to zone 3. Capable of growing in poor
soil with full sun to part shade. Pruning is done in fall with the exception
of southernwood which is cut back in spring or summer. They require
full sun and dry well drained soil. Some species will go dormant in the
summer heat and sprout again when cooler temperatures return. This is
most prevalent with the silver mound varieties. Don't plant wormwoods
near anise, beans, caraway, fennel, peas and sage.
To harvest for future use in insect teas, dried arrangements or sachets
you will pick the upper portions of the stalks when they are in full flower and
there is no moisture on the plant. Generally flowering occurs after July. Be
sure to pick any damaged leaves off your stalks. Tie the stem ends together
in bundles. Hang them upside down in a shady spot. Let them air dry like
this for a few days. We then put them into glass containers with tightly screwed
down lids. Store in a dark place.
This is artemisia Old Man or aka Old woman. It has thick leaves and a spreading growth habit. The look of the plant resembles a chrysanthemum. The foliage almost sparkles in the sun or moonlight. It tends to sprawl so we have chosen to use it in a small moss rock wall. Here it is seen growing with sedum "golden acres" and creeping jenny.
Powis Castle sends out feathery branches that shimmer in a gentle breeze. The feathery leaves glow in the moonlight. A good accent or background plant. The stems may be harvested for your needs by cutting back halfway. The plant will respond by filling in more fully. In this instance Powis castle is growing successfully in a shade garden where it receives partial sun for 3 hours a day. It will get taller when grown in full sun.
Silver mound the more commonly seen ornamental wormwood lends its' graceful form as a border or filler plant. The mound shape just invites you to brush it with your hand. Not as aromatic as others it still makes for a good insecticidal tea. It has inconspicuous yellow flowers, gets about 12 inches high by 2 feet wide. The plants last for about 7 years and can be propagated from woody cuttings taken in March or October. The crowns may be divided in the fall for new plants. Here we have it in a stepped foundation planting along with goldflame spirea, crimson pygmy barberry and red robin potentillia.
Southernwood makes a great low growing hedge and can be grown near a chicken coupe to protect the birds from lice infestation. It has a wonderful lemony fragrance that is released when you brush your hands over it. This plant was cut back to about 3 inches high this spring. As you can see it bounces back into full form with no problem. Growing along with it are perennial sweet pea, rue (another extremely bitter herb), and lemon balm. They all get along nicely.