Costmary is neither compact nor tidy so give it room. The sweet minty leaves are used in potpourri and tea; at one time a digestive powder was prepared from them. Formerly used to flavor beer and ale - Alecost is another common name. As is Bible Leaf - pressed leaves were used as bookmarks in Bibles because they would repel silverfish. It was used regularly in wardrobes and closets to repel moths. Yellow button flowers.