Meadowsweet, Filipendula ulmaria, is a tall perennial of wet meadows and stream-sides, its frothy creamy flower-heads carrying a heavy sweet scent. It was one of the most valued of strewing herbs, laid on floors to sweeten a room, and it flavoured mead and ale, which may be the true root of its name (meadwort) rather than any meadow. It is named as one of the three most sacred herbs of the Druids by later writers, alongside vervain and water-mint, a claim of the classical and antiquarian record rather than of first-hand testimony.
In Welsh myth meadowsweet is one of three plants, with broom and oak blossom, from which the wizards Math and Gwydion conjure Blodeuwedd, the woman made of flowers, as a bride for the hero Lleu Llaw Gyffes in the Fourth Branch of the Mabinogion, a story that later turns dark when Blodeuwedd betrays her husband and is transformed into an owl as punishment, but that begins with meadowsweet as one of the very materials of a living, magically created woman. The plant's heavy, sweet scent, which some find overwhelming in quantity, is concentrated in the flower rather than the leaf, and country tradition held that too much meadowsweet brought indoors could cause headache or drowsiness, a folk observation that fits oddly well with the salicylate chemistry discussed below.