If you were to research the herb costmary online you would tend to find reference to it as a medieval herb, and your impression would be that it is seldom grown in modern times. This is such a shame because costmary, Tanacetum balsamita (Chrysanthemum balsamita) is a delightful sweet smelling herb that has many uses. In medieval times it was a strewing herb to cover odors, as well as a flavoring for ale (it was also known as Alecost because of this). Later, in Colonial times, costmary leaves were used as bookmarks, mostly in Bibles and hymnals, giving it another name; Bible leaf. It seems that during long church services the parishioners would take a refreshing whiff or sometimes chew on the leaf. So, what can it be used for today? Costmary is a lovely garnish for lemonades, iced teas and other beverages. When the leaves are young it can be added to fruit salads, cold soups and green salads. The fresh leaves can also be used much like geranium leaves by laying them in the baking pan before pouring in the batter. It makes a good addition to bath teas, and homemade astringents. The silverish foliage has a slightly minty aroma mixed with balsam that is refreshing.

Costmary grows best in full sun and a light, dry but fertile soil. It's a perennial that can grow up to almost 3 foot and it spreads similar to mint. If you can manage to give it a sunny corner in your garden it will be happy, and one plant will be plenty. Many gardeners complain it's invasive, which it can be. If you deadhead the blooms before they go to seed and pull up any roots that spread, it can be kept under control. I do this with my mint too, and as long as I stick to the maintenance it's fine. 

Costmary is hardy to Zone 4 and is propagated by root division. The seed is not readily available, so it's best to buy a plant. You can grow it in shade, but it will become leggy and won't bloom. I've seen quite a few resources labeling it a shade herb, but it really won't do its best in a shady location. It can be cut back to keep it from getting to full or tall. The leaves can easily be dried. Strip them from the stems and dry on screens, then store in containers to use in tea blends, potpourri or drawer sachets. You can also use the dried leaves in sleep pillows. The following combination is soothing:

2 parts dried roses
2 parts dried lemon balm
2 parts costmary
1 part whole cloves

Mix the herbs together and allow them to blend for a week or so in a dry, covered container. Sew two square pieces of fabric on three sides and turn. Place the herbs into the fabric and hand sew the last side. This can then be placed inside your pillow case.

Costmary leaves can also be used in the rinse water for linens after handwashing. In a glass bowl, place 2 tablespoons dried costmary and pour over about 2 cups boiling water. Allow this to infuse for 1-2 hours. Strain and use in rinse water.

Herbs are grown for many reasons; ornamental, aromatherapy, culinary or medicinal. I also think it is important to grow herbs in order to preserve a part of history. As we bring children out to the garden to show them plants, flowers and herbs, we can snip a leaf for them to touch, smell and sometimes taste. We can share some of its past and allow them to ask questions. It's a precious thought that some day they will do the same thing with their own children and grandchildren.