Joe Pye Weed - A Butterfly Magnet

Welcome to the first Drive-by Horticulture post to actually feature an instance of a horticulture drive-by! The plant in the spotlight today is a wildflower, native to Missouri and much of the lower two-thirds of the United States. Frequently you'll see Joe-Pye Weed growing along roadsides in moist areas.

The Drive-by:

Here's a photo of the plant as you might see it in the wild, on the side of the road:

Before you ask: no, I did not take this photo from my moving car. That would be dangerous. Would it have been as dangerous as parking your car down a side road and then walking along said road to snap photos of plants? I'm not sure! It's anyone's guess, really. 

It kind of stands out from the mass of other weeds, doesn't it? 

The Horticulture:

August can be a difficult month for people, especially so for gardeners. The explosion of the pastel-hued blooms of spring are all but a distant memory. Early summer flowering plants have had their time in the spotlight and are content to fade into the background with the onset of the dog days of summer. When August heat threatens to liquefy even inert cement blocks, the plant world, it seems, has taken a brief hibernation. There's no need for despair, as there are certain plants that feel the heat, shrug it off, and put on a good show. Joe Pye Weed is one of those plants:

Plant information:

Botanical Name: Eupatorium purpureum (botanical experts are currently reclassifying some of the plants in this genus, so the correct name may possibly be Eutrochium purprueum)
Common Name: Joe Pye Weed
Perennial Plant: Individual clumps will overwinter year after year
Cold Hardiness: Will grow in zones 3 - 9
Culture: Full sun, can take a little bit of shade but will start to lean if it's in too dark a spot. Likes to be kept moist and in soil with a decent amount of organic matter. Not a good choice for very dry or very shady locations.
Size: Dwarf cultivars are advertised as maxing out around 3-4 feet high, but mine is almost 6 feet tall. It's not a terribly wide plant; figure on it staying about half as wide as its height.
Flowers: Large, rounded inflorescences are attractive as buds in July, opening fully sometime in early-mid August. Flowers remain open and attract butterflies for about a month or so. Seed heads remain erect and serve as a source of food for birds into winter.
Wildlife Benefits: Butterflies!!! If you like butterflies, plant one or more clumps of Joe Pye Weed where you can see them easily. In my experience, these plants attract more butterflies over its bloom period than the famous Butterfly Bush (Buddleia)

History: Joe Pye Weed has properties that rendered it useful for herbal medicine in the 17-1800s, particularly the treatment of various fevers. The name is said to come from either 1) a Native-American healer named, appropriately, Joe Pye, or 2) the phonetic translation of jopi, a Native American word for tpyhus. If you're interested in the whole story, mosey on over to a blog post on PrairieWorks.com: Joe Pye - The Name Behind the Legend

Even though these plants don't bloom until late summer, that's not to say they're unattractive the rest of the year. My plants have historically been one of the latest perennials to emerge from the ground in spring, gradually turning into an attractive medium-dark green backdrop for other plants. Some cultivars have red or purplish stems:

While you may be tempted to call the large mass of pink on the top of each stem a single flower, it's actually an organized arrangement of many tiny flowers. This is called an inflorescence. Look at the photo below: You can pick out each one of the individual cylindrical flower buds. When buds open, the mass just looks like one giant flower. 

When I said butterflies like this plant, what I meant was that butterflies love this plant:

Take a look at the full-res picture; there are at least 8 butterflies here

Black Swallowtail

Eastern Tiger Swallowtail

There's room for everyone!

If you're in the mood for a big plant - and I mean a big plant - and have plenty of room in your garden, there are other varieties of Joe Pye Weed that might be of interest. One in particular is called 'White Joe', aptly named for its white flowers. The nursery where I work has a clump of it that's about twelve feet tall and at least six feet wide. The butterflies love it just as much as a dwarf plant!

Don't let the scraggly look put you off; this is what Joe Pye Weed looks like when it's planted in dry areas. A little more moisture and this would be gorgeous. Still, a plant this big needs shorter companions in front of it.

For scale, compare the size of the butterfly relative to the flowers here and on the photos above. See? BIG!

Where to buy:

Plant Delights Nursery

Niche Gardens here, here, and here