GLENCOE, Ill. (June 25, 2007)—The Chicago Botanic Garden is releasing results of an eight-year study on Catmints, Nepeta, in its 29th issue of Plant Evaluation Notes: “A Comparative Study of Cultivated Catmints.”

Catmint is part of the mint family (Lamiaceae), which includes the garden favorites giant hyssop (Agastache), bee balm (Monarda) and lamb’s ears (Stachys), as well as aromatic herbs such as lavender (Lavandula), rosemary (Rosmarinus) and thyme (Thymus). Catmints are dependable garden plants prized for their abundance of flowers, long season of bloom and striking foliage. Gardeners tend to favor catmints for their easy culture and landscape versatility. Just recently, the Perennial Plant Association named Nepeta ‘Walker’s Low’ the 2007 Perennial Plant of the Year.

The Chicago Botanic Garden evaluated 36 taxa of Nepeta between 1999 and 2006 to identify outstanding selections through an assessment of their ornamental traits, disease and pest resistance, cultural adaptability and winter hardiness. Thirty taxa successfully completed a minimum four-year trial, although some taxa were evaluated for the full eight-year period.

Catmints tend to thrive in full sun and well-drained soils, and some are drought-tolerant once established. However, Nepeta subsessilis is adaptable to partial shade and prefers moist soils. Disease and pests rarely affect catmints, but their health and vigor will quickly decline in poorly drained soils. It is not necessary to add fertilizer, as that will only encourage floppy stems.

In general, the catmints were well adapted to the growing conditions of the test site, which included full sun and well-drained clay-loam soil. They proved to be hardy in winter and were not affected by disease or pests. Twenty-two of the thirty catmints that completed the trial were highly rated for heavy flower production, robust plant habits, good health and winter hardiness. Four taxa received five-star excellent ratings for their overall performance including N. ‘Joanna Reed’, N. ‘Six Hills Giant’, Nepeta x faassenii ‘Select Blue’ and Nepeta racemosa ‘Walker’s Low’.

The majority of catmints were consistently strong bloomers, often with flower production above 80% during the peak bloom period -- two to three weeks after the first flowers opened. Maintenance practices were kept to a minimum throughout the trial to simulate home garden culture. Most cultivars continued to bloom without deadheading and plant health improved on its own within a few weeks after the primary bloom cycle ended.

Catmint flowers are clustered in many-flowered verticillasters (false whorls) above the foliage. Flower color ranges from purple-blue to lavender and white, although Nepeta govaniana has yellow blossoms. Catmints have a long bloom period, beginning in late spring to early summer and continuing well into late summer and fall. Catmints are free flowering, easy-care perennials combining handsome foliage with an exuberant floral display. Their adaptability to average gardens as well as droughty conditions attests to their landscape versatility.

The Chicago Botanic Garden’s Plant Evaluation Notes provide the latest information on plants suited to the Midwestern climate and growing conditions. Cost is $3 per copy. To obtain Issue 29, “A Comparative Study of Cultivated Catmints,” write:

Plant Evaluation Notes
c/o Richard Hawke
Chicago Botanic Garden
1000 Lake Cook Road
Glencoe, IL 60022