Catnip has all the characteristic earmarks of a member of the mint family:
stems square in cross-section, leaves opposite and fragrant, and small flowers
in tight clusters at the ends of branches. This perennial herb may grow up to 3
feet tall and be highly branched. The gray-green to green leaves are
heart-shaped with scalloped edges and are often crowded toward the top of the
plant. The flowers are white, dotted with purple, two-lipped, and produce four
tiny, dark nutlets per flower.