These are generally large plants with big domes of small flower heads that are rich in nectar and pollen. Blossoms attract butterflies. Most of the species described here are native to meadows of the eastern and central U.S.; popular in perennial borders and naturalistic meadow plantings.
E. cannabinum. HEMP AGRIMONY. Native to Europe. Grows 56 ft. tall, 4 ft. wide, with opposite pairs of deeply cut, 5-in.-long leaves and broad clusters of fluffy white, pink, or purple flowers in the summer. 'Album' produces white flowers; 'Plenum', pinkish purple blooms. Ample water.
E. dubium 'Little Joe'. DWARF JOE-PYE WEED. From eastern U.S. To 4 ft. tall and about as wide. Large domes (to 10 in. across) of small lavender flowers are held above whorls of deep green foliage in late summer and fall. 'Baby Joe' is even smaller, at 2212 ft. high and wide. Moderate water.
E. greggii. GREGG'S MIST FLOWER. Native to Arizona, Texas. Weak-stemmed plant to 12 ft. tall, 23 ft. wide, with clusters of fluffy lavender flowers similar in form to those of floss flower (Ageratum). Blooms from spring to fall. Lacy, divided, light green leaves are somewhat hairy and usually sparse. Excellent for attracting butterflies. Native to dry, hot, rocky places but prefers some shade in low desert. Drought tolerant but looks best with occasional water. 'Boothill', first found near Tombstone, Arizona, is a choice form.
E. maculatum. SPOTTED JOE- PYE WEED. Similar to E. purpureum but smaller (to 6 ft. tall, 3 ft. wide at most), with green stems speckled or blotched in purple. Flat-topped clusters of pink, purple, or white flowers bloom from midsummer to early fall. Commonly sold is 'Gateway', to 5 ft. tall, with dusky purplish rose flowers at the tops of purplish stems. Give ample water, rich soil.
E. perfoliatum BONESET. Grows to 35 ft. tall and 23 ft. wide. Long (8-in.), narrow, medium green leaves are joined at their bases, so that the stem seems to grow through the leaves. Blooms from late summer to fall, with fluffy white flowers in flat-topped clusters. Attractive in meadow restoration, but poisonous to cattle and thus considered a nuisance by ranchers. Best with regular to ample water but takes considerable drought. In the past, it was thought to have medicinal value, helping to knit broken bones (hence the common name).
E. purpureum. JOE-PYE WEED. Often sold as E. fistulosum. Native to damp meadows in the eastern U.S., this imposing plant deserves wider use. Clumps of hollow stems reach 39 ft. tall and 13 ft. wide. Whorls of medium green, strongly toothed leaves to 1 ft. long; leaves have a vanilla scent when bruised. Dusty rose flowers, which are attractive to butterflies, appear in large, dome-shaped clusters in late summer or early fall. 'Carin' grows 57 ft. tall, has dark purple stems topped by silvery pink flowers. 'Little Red' is smaller to 4 ft. high and has pinkish purple flowers. Ample water.
E. rugosum. WHITE SNAKEROOT. Zones US, MS, LS; USDA 6-8. To 4 ft. tall, 2 ft. wide. Stems and lance-shaped, gray-green leaves to 5 in. long are heavily marked with deep brownish red; 'Chocolate' has especially dark color. Fluffy white flowers in late summer and early fall. Give rich soil, ample water.