Costmary, Tanacetum balsamita, is one of those herbs that used to be in every herb garden but is now rarely seen. It was used medicinally and like other plants associated with the virgin Mary, was used for women’s issues, mainly to bring on menstruation. For that reason, it should never be used internally by pregnant women because it could cause a miscarriage. One of its nicknames, alecost, refers to its use to flavor ales and spiced wines.
The leaves contain fragrant oils making it useful as a strewing herb. The scent is similar to balsam. The oils also keep away silverfish, so costmary leaves were often tucked into the pages of family bibles to protect them from damage during a time when books were expensive. Another convenient use of the leaves as bookmarks was that congregants could surreptitiously sniff the leaves in church to keep themselves awake during long and sometimes boring sermons.
Costmary is a member of the aster family. It is a perennial herb native to the Mediterranean area. It is hardy to zone 4. While it will do well in regular garden conditions, it prefers to be dry making it a candidate for a xeriscape. Costmary prefers full sun but can tolerate some shade. The plants reach a height of 3’ to 4’ with leaves up to 1’ long and 2” wide. The flowers are small yellow disks similar to tansy flowers. Costmary will only flower if grown in full sun. If grown in shady conditions, it will grow more and bigger leaves. Plants should be divided every 3 years to keep them healthy.
Although most people buy plants, costmary can be grown from seed. Surface sow the seeds. They need light to germinate. Lightly press the seeds against the soil and keep them evenly moist, not wet, until germination. Seedlings can be transplanted into your garden when they reach 6”.
Harvest and dry the leaves from your costmary and use them in potpourri, sachets or to scent your bathwater, alone or in combination with other herbs, for a soothing bath.
4 Comments on “Costmary”
Hmmm. In May I planted seedlings in deep buckets and am disappointed that my first year harvest is so meager. The leaves are small (5″), the stems short (additional 3 “) and the fragrance weak. How to improve? I was getting 5-6 hours of sun per day. They started to give fresh new leaves in addition to the original ones, only after over a week of heavy rain. I am in zone 7 (Seattle type climate). I am thinking to separate the bunches which are all together in the center of the pot
If your plants are crowded into the center of the pot, then they definitely need to be separated, preferably one plant per pot. Also, these are drought tolerant plants meaning they like to be dry so if you are living in a wet climate, they may be getting too much water which also affect their growth.
I planted mine in a row in our field, here in SW Missouri, never watered it once established, and eventually never weeded around it. It spread vigorously and lived there for over 10 yrs.
I’ve had Costmary for years, can’t even remember where I got it. This hot summer has produced bigger, sweeter leaves than ever, some nearly a foot long and four inches wide. (I could make a Covid mask from mine!) It has also seemingly spread on its own. I’m very pleased with this, as I’ve not seen anywhere to purchase the plants. Sadly, garden centers have less and less diversity, just the basics herbs in several varieties.
Gave some to my girlfriend a year or two ago, but she is surrounded by tall trees and the plants lack sun and remain stubby.