Woodruff is a European import that has made itself at home in our woods. Although it can form fairly dense mats, it does not seem to take over very quickly, so we may provisionally regard it as a welcome visitor. It came to these shores for its strong scent, which is used in potpourris and as a flavoring; but it is also notable as a singularly attractive ground cover.
Gray describes the Genus Galium thus:
GALIUM L. Bedstraw. Cleavers Calyx-teeth obsolete. Corolla wheel-shaped, valvate in the bud. Stamens 4, rarely 3, short. Styles 2. Fruit dry or fleshy, globular, twin, separating when ripe into the 2 seed-like indehiscent 1-seeded carpels. — Slender herbs, with small cymose flowers (produced in summer), square stems, and whorled leaves, the roots often containing a red coloring matter. (Name from gala, milk, which some species are used to curdle.)
Although Gray does not describe the species G. odoratum, it is easily distinguished: it is the only member of its genus in our area with dense showy clusters of relatively large (for a bedstraw) white flowers and a uniform upright habit.