University of Vermont
Department of Plant and Soil Science

Summer News Article
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PERENNIAL PLANT FEATURE:  JOE-PYE

Dr. Leonard Perry, Horticulture Professor
University of Vermont

The common name of Joy-Pye weed doesn’t do justice to this late summer-blooming hardy perennial, which has gorgeous blooms over a six-week period, or longer, and is low maintenance.  Most species are native wildflowers of the eastern United States, good for pollinators.  There are selections from under two feet tall to over 6 feet tall, for small spaces to backs of borders.
   
The genus or entire grouping of Joe-Pyes is in the aster family, and used to share one genus name (Eupatorium) until botanists recently reclassified them into several others.  Most that you’ll find, and which tend to grow five feet or higher, are in the same genus (Eutrochium).  The few under two feet tall are now in a different genus (Conoclinum). 
  
‘Chocolate’ is one you’ll often see which has dark, almost black, leaves and contrasting white flowers.  It is in yet another genus (Ageratina altissima).  Although “altissima’ means tall, this one only gets to about three feet high at best.  Often you’ll see it listed as growing in USDA zone 4 or even 3 (-20 degrees F or lower in winter), although I’ve never had luck growing it in this zone.  More reliable would be USDA zone 5 (-10 to -20F in winter).
   
Actually, the name Joe-Pye correctly only refers to some species, and even these need other names such as “spotted” or “sweet-scented”.  Perhaps the most common origin to the name is the story of a Native American medicine man, Joe Pye, who used one species (purpureum) to treat various ailments.  Another common name, “boneset”, refers to its past use as a pain reliever for bone pains from fevers. 
   
While most species need full sun (6 hours or more direct sun a day), the white snakeroot Joe-Pye (Ageratina altissima) will tolerate part shade (3 to 6 hours of direct sun).  While most form clumps, the hardy ageratum Joe-Pye (Conoclinum) spreads by underground stems called “rhizomes”.  ‘Cori’ is a lavender-blue cultivar (cultivated variety) of this genus, while ‘Album’ is a white cultivar.  Flowers of these are very similar to the annual bedding ageratum.
   
Joe-Pye species tolerate a range of soils but, in general, prefer moist and average to fertile soils for best growth.  The spotted Joe-Pye (E. maculatum) and hollow Joe-Pye (E. fistulosum) both grow naturally in, and prefer, moist to wet soils.  During dry periods, or if soils aren’t wet, these will need additional water to prevent wilting.  A white cultivar of the latter grows to eight feet tall and may be seen with the name ‘Bartered Bride’, or more politically correct name of Joe-Pye’s Bride.  As you might guess, stems are hollow. One of the most common cultivars of the former species, ‘Gateway’, has pink flowers and grows over six feet tall.
   
Joe-Pye perennials need little fertilizer if soils are rich, perhaps an organic one in spring, or merely side-dressing around plants with compost.  In early summer, taller selections can be cut back by one-third to one-half.  This will keep them shorter, bushier, and blooms will not appear too much later than normal.  Even without cutting back, taller selections seldom need staking.  Since deer don’t like this plant, you don’t have to worry about them pruning plants.
   
You may want to “deadhead”, or remove flowers once finished, to keep plants from prolifically self-sowing all over your garden.  Or, if not an issue (seedlings are easy to weed out next spring), leave the seedheads to provide seeds for birds. The only potential problem, and at that one plants can tolerate, is the white powdery mildew disease on leaves.  Some selections have good resistance to it while, with others, the disease varies with cultivar and season.
  
Joe-Pye are good in backs of borders, natural areas, or moist meadow plantings.  Lower cultivars (five feet or less tall), such as ‘Little Joe’ with purple flowers, ‘Baby Joe’ with light purple flowers, or ‘Phantom’ with purplish-pink flowers, can be used  in the middle of beds and borders.  Joe-Pye combines well with many perennials, including bee balm, coneflowers, rudbeckia, Siberian iris, blue perennial lobelia, turtlehead, and ornamental grasses. 
   
As part of his ongoing extensive perennial evaluation at the Chicago Botanic Garden (USDA zone 5), trials manager Richard Hawke evaluated a couple dozen selections of Joe-Pyes and their relatives over a 10-year period.  Those receiving five-star ratings for best growth, flowering, habit, and disease resistance included ‘Chocolate’ hardy ageratum, ‘Little Joe’ coastal plain Joe-Pye, and two hollow Joe-Pye—the pale pink ‘Carin’ and white ‘Bartered Bride’. In addition, six other cultivars got four-star ratings for their strong growth and performance.
   
You can learn more about this great garden plant, and details of the Chicago evaluation, at their website (www.chicagobotanic.org/research/).  You’ll find results of this and three dozen other trials under “plant evaluations”, which is linked under the “ornamental plant research.”


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