Catmints are widely adapted, dependable, easy-care perennials. There are more than 20 species commonly available, and some flower better and have a more attractive growth habit than others. To determine the best varieties for home gardeners, the Chicago Botanic Garden grew 36 different catmints over an eight-year period -- from 1999 to 2006, evaluating them for ornamental traits, pest and disease resistance, hardiness, and adaptability to soil and environmental conditions. They were grown in full sun on well-drained soil with minimum maintenance. (Poor soil drainage is usually the downfall of catmints.)
The top catmints featured abundant lavender flowers from spring to fall without deadheading, and healthy green foliage. Four catmints received 5-star ratings -- the highest possible. 'Joanna Reed' grows 24 inches tall and 48 inches wide. 'Six Hills Giant' and 'Walker's Low' grow 30 inches tall and 48 inches wide. 'Select Blue' is a low grower reaching only 14 inches tall and 30 inches wide. Eighteen other catmints received 4-star ratings and were deemed good choices for many gardens.
For more information on this study, go to Issue #29: A Comparative Study of Cultivated Catmints at: Chicago Botanic Garden.