Eupatorium ageratoides is a member of the Asteraceae, commonly called White Snakeroot. It produces white flower heads that are in bloom from July to October. Plants known as white snakeroot (Ageratina altissima) are poisonous, so confirm identification and handling guidance before planting.

White Snakeroot (Eupatorium ageratoides) bears white flowers from July to October and belongs to the Asteraceae.

https://en.wikipedia.org/wiki/Ageratina_altissima

Ageratina, commonly known as snakeroot, is a genus of over 300 species of perennials and rounded shrubs in the family Asteraceae.

Eupatorium ageratoides

White Snakeroot | Eupatorium ageratoides

A perennial with double flowers, Eupatorium cannabinum 'Plenum' reaches about 1.5 metres and produces its blooms from July to October. It belongs to the Asteraceae family and carries the fuller-flowered form of hemp-agrimony. Plant in moist to wet soils — sandy, loamy or clay — in full sun or partial shade. Fully hardy (H7) in UK gardens and suited to damp borders and wild garden corners.

Hemp-agrimony 'Plenum' is a double-flowered perennial to 1.5 m for moist, sunny or partly shaded sites, flowering from July to October.

https://en.wikipedia.org/wiki/Eupatorium_cannabinum

Eupatorium is a genus of flowering plants in the family Asteraceae, containing from 36 to 60 species depending on the classification system. Most are herbaceous perennials growing to 0.5–3 m (1.6–9.8 ft) tall.

Eupatorium cannabinum 'Plenum'

Hemp-agrimony 'Plenum' | Eupatorium cannabinum 'Plenum'

Eupatorium fistulosum 'Ivory Towers' is a cultivar of Eupatorium (family Asteraceae) valued for its late-season flowering. It produces blooms from July to October. The selection name 'Ivory Towers' identifies this particular strain within the species. Its long flowering period makes it useful for extending nectar availability into autumn.

Eupatorium fistulosum 'Ivory Towers' flowers from July to October, extending late-season nectar and colour in borders and damp garden corners.

Eutrochium is a North American genus of herbaceous flowering plants in the family Asteraceae. They are commonly referred to as Joe-Pye weeds.

Eupatorium fistulosum 'Ivory Towers'

Hollow Joe-Pye Weed | Eupatorium fistulosum 'Ivory Towers'

Eupatorium mac. 'Red Dwarf' is a clump-forming member of the Asteraceae with deciduous foliage and a flowering season from July to October. It suits sites in full sun or partial shade and tolerates clay or loam soils across a wide pH range. The cultivar accepts both moist but well-drained and poorly drained conditions and will grow in exposed or sheltered positions. Its compact clump habit makes it useful toward the rear of herbaceous borders and in informal planting schemes.

Eupatorium mac. 'Red Dwarf' is a clump-forming Eupatorium that flowers from July to October and suits clay or loam soils in sun or partial shade.

Eupatorium mac. 'Red Dwarf'

Eupatorium purpureum is a tall perennial in the Asteraceae that reaches about 2.0 m and carries a sweet-scented display of summer flowers. It flowers from July to October and favours full sun in soils that remain moist but are well-drained. Fully hardy in the UK (H7), it tolerates sandy, loamy or clay soils. Plant where its height and scent can be appreciated, for example at the rear of a mixed border.

Joe Pye Weed (Eupatorium purpureum) is a tall, sweet-scented perennial that flowers July to October and suits full sun in moist, well-drained soils.