One of the most stunning plants in a late season garden, Joe-Pye weed dazzles with large clusters of pink, purple, or white flowers on plants that can rise as high as 6 or even 8 feet tall. These towering beauties add drama to the fall garden, but not everyone has enough space to use such expansive growers. Fortunately, breeders have come up with more restrained cultivars, such as the aptly named 'Little Joe' and 'Baby Joe' that fit more easily into many landscapes. Joe also has a number of attractive relations that add interest to the autumn garden, including hardy ageratum and white snakeroot. All do best in moist soil in full sun to light shade, and all are butterfly magnets.
If you were familiar with these plants as members of the Eupatorium genus, prepare to learn some new names. Those pesky taxonomists have been at work and now the plants commonly called Joe-Pye weed are classified in the genus Eutrochium. White snakeroot, of which the dark purple-leaved cultivar 'Chocolate' is probably most commonly planted, is now Ageratina altissima, while lavender blue-flowered hardy ageratum is now Conoclinium coelestinum. (And no one is sure who Joe-Pye really was; some say he was a Native American medicine man who used his namesake plant medicinally.) So you may see either the new names or the older ones in catalogs and references and on plant tags.
To help you choose the best among these varied plants, the Chicago Botanic Garden has just released the results of a 4-6 year evaluation of 26 taxa of Eutrochium and related genera done at its USDA Hardiness Zone 5b and AHS Heat Zone 5 garden. Plants were rated on a scale of one to 5 stars. Four plants received a 5-star rating: 'Chocolate' white snakeroot; 'Little Joe' coastal plain Joe-Pye weed (E. dubium); and two cultivars of hollow Joe-Pye weed (E. fistulosum), 'Carin' and 'Bartered Bride'. All showed superior flower production, robust growth, and good disease resistance and winter hardiness. Additionally, there are quite a few others that achieved 4-stars.
To learn more about Joe-Pye weed and see the complete evaluations, go to Chicago Botanic Garden.