University of Vermont
Department of Plant and Soil Science
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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