Plant · P-660

Costmary

Tanacetum balsamita

This rhizomatous perennial's balsam-and-mint-scented leaves flavored beer before hops took over the job, which is where the old name alecost comes from, and dried sprigs were tucked into hymnals and bibles as a natural air freshener and bookmark. The leaves also season salads, soups and tea, though the essential oil can run heavily to thujone, so it is better kept to culinary amounts than steeped as a strong medicinal tea. A single plant spreads into a patch by shallow rhizomes, easy to hold back with a mown edge or by dividing the outer ring every couple of years. It flowers only in full sun; in part shade it stays leafy but produces almost no bloom.