Sunday, July 23, 2017

Make Room for Joe Pye

Butterfly on Eutrochium maculatum 'Gateway'
Some plants shout their season to me when I see them. Bloodroot (Sanguinaria canadensis) is very much spring, and goldenrod (Solidago) is a quintessential fall. Joe Pye weed (Eutrochium spp.) is a definite summer plant. Just when it gets unbearably hot, Joe Pye weed opens up a dome-like inflorescence of tiny flowers, delighting dozens of pollinators and giving them sustenance through the hot days.

There are three different species of Eutrochium (all formerly considered part of Eupatorium) in Georgia. The common name “Joe Pye weed” comes from a story that a Native American named Joe Pye used the leaves of it to brew a tonic that helped people with fevers in the late 1700’s or early 1800’s. Four species are found in New England, where the story originates, so it’s not clear which species might have been used.

Eutrochium purpureum (purple at the node)
Of the 3 species in Georgia, it is often confusing which ones are which so let me go over each one. Sweet-scented Joe Pye weed (Eutrochium purpureum) is found naturally in north Georgia with a few scattered southern locations reported. The Field Guide to the Wildflowers of Georgia describes it topping out at 6 feet but I’ve never seen one over 4 feet myself. It is normally found in “moist, upland, hardwood forests” where the reduced light often keeps it short and provides only for a modest flower cluster containing sweetly-scented flower heads of 4-7 tiny florets. The mostly green stem is purple at the leaf nodes and hollow only at the base.

Spotted Joe Pye weed (Eutrochium maculatum) is limited in its natural range in Georgia with reports of it being found only in Murray and Union counties (in the Blue Ridge ecoregion). The reddish, sometimes spotted stem is characteristic of this species; it also generally reaches up to 6 feet tall. Other differences include the number of florets per head being more numerous (9-22 per head) and the overall inflorescence shape being more flat than dome-shaped (good pictures here). I think the flower color is generally a deeper pink as well. This is the species from which the shorter cultivar ‘Gateway’ was developed; that cultivar is said to be 4-5 feet tall. I have found that it does well in pots if kept moist. 

Etrochium maculatum in the wild (fairly flat top)
E. maculatum stem (not hollow)

Eutrochium fistulosum with hollow stem
Hollow Joe Pye weed (Eutrochium fistulosum), also called trumpetweed, is probably the one that most of us see reaching up to 11 feet on wet roadsides in north Georgia and scattered southern locations. If you were to cut the stems, you’d see that they are hollow throughout, unlike the other two species. There is also a whitish cast to the stem.

Florets are fewer than maculatum, usually 5-7 per flower head, but the inflorescence itself is large and dome shaped. Flower color varies from pale to medium pink.

Eutrochium fistulosum
before florets open
Eutrochium fistulosum
with florets open

Eutrochium maculatum with about 11 florets per flower head.

Other E. maculatum cultivars besides ‘Gateway’ include ‘Atropurpureum’ and ‘Phantom’ as well as a few others.  E. dubium ‘Little Joe’ and ‘Baby Joe’ are both from a species native to the coastal areas of the East Coast. E. fistulosum cultivars include ‘Carin’ plus others, including some white selections such as ‘Bartered Bride’ and ‘Ivory Tower.’

You can read about Eupatorium “family” plant trials in Chicago in a report published here in 2014. It includes names of cultivars and detailed descriptions but the recommendations may not be as appropriate for Georgia.

1 comment:

  1. Ellen, from what I understand, the Europeans can't get enough Joe Pyeweed -- it is an amazing design element (as well as pollinator plant). It's sad that we Americans do not appreciate the fantastic plants we have in our midst (if we don't remove and replace with exotics).