Eupatoriums are a very important plant genus for gardeners in CT. They offer beautiful flowers that support pollinators of all sorts. They are in the aster (Asteraceae) family. They bloom for a long time, usually 5-6 weeks.
Most of the taller Eupatoriums benefit from pinching in June to make them fuller and to help avoid having to stake them. You can also pinch half of the plant to double the bloom time or pinch 1/3 of the plant in early June and 1/3 of the plant in late June to triple the bloom time.
All Eupatoriums will self-sow, some more rampantly than others. If this becomes a problem, deadhead them after blooming before their seed pods ripen (turn fluffy).
Who was Joe Pye?
Some researchers believe he was a native American Mohican sachem (chief) named Schauquethqueat who lived in Stockbridge, MA from 1740-1785. He took the Christian name Joseph Pye. Legend has it that he used the plant for medicinal purposes in his community.
***Note that many of the Eupatorium scientific names have changed. The new names are in parentheses. It is very important to know this as many people study lists that use the new names.
Eupatorium coelestinum (Conoclinium coelestinum) -Perennial ageratum
Northeastern US native
Rhizomatous, makes an excellent taller ground cover/green mulch.
Late to emerge in spring. Excellent choice to plant with spring blooming bulbs or early blooming perennials.
Grows 2-3’ tall. Excellent cut flower. Bloom August thru early October.
‘Wayside’- a more compact, shorter variety growing 18-24” tall
Eupatorium dubium (Eutrochium dubium)- Joe-Pye weed
Northeastern US native
Huge heads of mauve-purple flowers. Grows 3-5’ tall. Flat flower clusters. The best choice for near the seashore as it is salt tolerant.
‘Baby Joe’-compact form, 2-3’ tall and 1-2’ wide. Flowers are magenta-purple.
‘Little Joe’- compact form growing 3-4’ tall and 1-3’ wide. Stiff, upright habit, light lavender flowers
'Mask'- A compact form growing 28-40" tall. Domes of pink flowers and purple stems make this a great choice for containers or smaller gardens.
Eupatorium fistulosum (Eutrochium fisulosum) – Hollow Joe-Pye weed
Northeastern US native
Stems are hollow and purple tinged. Stems are primarily smooth with very few hairs.
Large dome-shaped heads of lavender-pink flowers are dome shaped. A large growing plant reaching 4-7’ tall. Leaves are long and strappy, usually 5 or more per whorl.
Eupatorium fortunei
Native to Asia
‘Pink Elegance’- Green and white variegated, pointed foliage. Fuzzy pink flowers in September. Flowers are very attractive to pollinators. 3-4’ tall
‘Pink Frost’-Japanese Joe Pye weed has variegated green and white leaves. Deep pink flowers in September. 2-3’ tall.
Eupatorium hyssopifolium- Hyssop leaf thoroughwort
Northeastern US native
Thin, more delicate textured leaves. Flat-topped umbels of white flowers on 3-4’ tall stems. Benefits from a hard pinch in June to avoid flopping. Grows best in full sun and well-drained soil.
Eupatorium maculatum (Eutrochium maculatum) - Spotted Joe-Pye weed
Northeastern US native
Stems are purple spotted and pubescent (hairy). Flat topped flower clusters of lavender-pink. Straight species will grow 5-8’ tall. Often found growing in wetlands
‘Atropurpureum’- will grow 2-5’ tall depending on moisture in the soil. Large domes of lavender-purple flowers with a silvery effect to the blossoms.
‘Euphoria Ruby’-Short, compact, well branched plant growing only 2’ tall. Very floriferous with mounds of darker reddish-purple flowers.
‘Gateway’-Giant, stately, tall plants can grow 7-10’ tall with flowers the size of bushel baskets. Benefits from a hard cut back in June.
‘Purple Bush’-Dark lavender-purple flowers on 5’ tall plants.
Eupatorium perfoliatum- Boneset
Northeastern US native
Perfoliate or clasping leaves, white flowers
Grows 2-4’ tall depending on the amount of moisture in the soil. August-September blooming
Eupatorium purpureum (Eutrochium purpureum) -Sweet Joe-Pye weed
Northeastern US native
Stems purple at the nodes only (where the leaves connect) and not hollow. Stems are primarily smooth with very few hairs. Leaves are matte in texture, usually 3-4 in a whorl. Flowers are dome shaped and slightly fragrant. This is the most drought tolerant Joe-Pye weed and can be found in partially shade, upland woods. The straight species is 4-7’ tall, 2-3’ wide
‘Little Red’- a compact form with rich rosy-pink domed flower heads. Grows 5-6’ tall.
‘Ruby’- Very compact variety topping out at 3’ tall. Flowers are rosy-pink and vanilla scented.
Eupatorium rugosum (Ageratina rugosum) -White snakeroot
Northeastern US native
This plant is poisonous. It self-sows prolifically and can take over a garden area. Will grow in partial shade or sun.
‘Chocolate’ has purple leaves and white flowers. It has the best purple color in full sun. It will self-sow but many of the seedlings will have green leaves.