Nepeta x faassenia, commonly called nepeta, nepeta catmint, or Faassen's catmint, is one of several perennial catmint plants. This one is a horticultural hybrid developed by crossing Nepata racemosa with N. nepetella. It is, therefore, a sterile plant that will not come true from seeds.
The nepeta genus includes roughly 250 species. Many are perennials, some are annuals, and some make good ground covers, though they can be overly aggressive in favorable locations.
Nepeta x faassenii is one such species that makes for a good ground cover, since it has the ability to crowd out weeds. The 'Six Hills Giant' cultivar is a good choice for covering large areas. While it is not a spreader, it is large enough to take up space as the spring and summer months advance. Growing as high as 36 inches, it blooms all summer long with purple flowers.