Karl Foerster feather reed grass and fountain grass
Eupatorium is one of my favorite perennials at this time of year. There are a number of different species (fistulosum, maculatum, purpureum, all North American natives), and you can find cultivars, hybrids and selections from these species.
Of Eupatorium in general, perennial expert Allan Armitage writes:
"One must often search high and low for its presence in American gardens. One the other hand, it is one of the architectural building blocks of British gardens. People with whom I have traveled overseas in the fall always wonder why our native plant is so well used and cherished there and so scorned and ignored here." (Herbaceous Perennial Plants, 3rd Edition, 2008)Commonly known as Joe Pye weed, to my mind, this plant doesn't merit the "weed" part of its name. Yes, it can self-seed, but I haven't found that to be troublesome, and this is easy to prevent by deadheading.
As for the name, here's Armitage again:
"Joe Pye is said to have been a North Carolina Indian who used these plants to cure many ailments, including typhoid fever, and the plants became known as Joe Pye's weed. Perhaps changing the name to Joe Pye plant would enamor it to gardeners a little more."
We have Joe Pye plants growing wild along the creek that flows through a corner of our property, and a few years ago we collected seed and propagated plants to populate a low wet area near our pond. It's interesting to see how much smaller the flower heads are on the wild species.
If you've got a country garden, be sure to include this plant. It makes a great companion to ornamental grasses and other late flowering perennials. It's also long-blooming, attractive to butterflies, and provides a welcome dusky pink color when so many other late bloomers seem to be yellow (all those rudbeckias, for example).
Cultivars to look for: I can't quite remember which cultivar the Eupatorium in the pictures at the top of this post is: from its rather large flower heads, red stems, and tall habit (about five feet), I'm guessing 'Atropupureum'. According to Armitage, the big purple-flowered species aren't easy to tell apart, and many of them have hybridized, which makes them even harder to sort out.
Another well-known cultivar is 'Gateway', which grows five to six feet tall (even though it was said to be a dwarf when it was first marketed). If you're looking for a dwarf, your best bet is Eupatorium 'Phantom', a hybrid of E. maculatum 'Atropurpureum' and E. rugosum that grows three to four feet tall.