This aromatic, flowering landscape herb grows in mounds of soft gray-green leaves covered with a haze of shimmering lavender-blue flowers. Easy to grow, catmint makes a beautiful spreading ground cover that blooms for weeks on end. Plant it under roses, in an herb garden, at the front of perennials or to cover bare corners of the garden with a soft wave of color. Many house cats adore its fragrance as much as its less attractive relative, catnip.