Easily grown in average, medium to wet, well-drained soils in full sun to part shade. Prefers full sun in moist, humusy soils, however, plants do well in light shade and generally have better shade tolerance than most other species of Eupatorium/Ageratina. Deadhead spent flower heads to avoid any unwanted self-seeding (cultivar does not come true from seed).
This cultivar features small white fluffy flowers (composites with rays absent) arranged in rounded, broccoli-sized heads (corymbs to 6" across) atop shiny purple stems typically rising 3-5' tall. Sharp-toothed, lance-shaped to elliptic-oblong leaves (4-7" long) are chocolate-tinted, thus giving rise to the cultivar name. An exclusive introduction of the Mt. Cuba Center of Greenville, Delaware.
No serious insect or disease problems. Leaf miners are sometimes attracted to the foliage. Self-seeding can border on being aggressive in optimum growing conditions.
Borders, cottage gardens, wild gardens, woodland gardens and naturalized areas.