Ageratina altissima (White Snakeroot)

Ageratina altissima (White Snakeroot) is a clump-forming, spreading, herbaceous perennial boasting flat-topped clusters of small, fluffy, bright white flowers in summer and fall. Borne atop erect, strong branching stems, the long-lasting blossoms are attractive to bees, butterflies and moths in search of nectar. Long-stalked, sharp-toothed, gray-green, nettle like leaves, 3-6 in. long (7-15 cm), are paired along the stems. Native to North America, White Snakeroot provides a wonderful garden presence and late season flowers at a time when choices may be limited. Use it in the informal setting of a cottage garden or allow it to naturalize in a woodland garden.

• Grows up to 3-5 ft. tall (90-150 cm) and 2-4 ft. wide (60-120 cm). Will spread by rhizomes and self-seeding where happy.
• Performs best in part shade in humus-rich, moist, alkaline soils.
• Very useful and adaptable in the garden, this is an excellent choice as an accent plant, or for mixed borders, cottage gardens, woodland gardens, wild gardens and naturalized areas.
• No serious insect or disease problems. Deer resistant.
• Cut back faded flower stems to base to avoid any unwanted self-seeding.
• Propagate by seed or division, in spring.
• Native to North America.
• Toxicity: Ageratina altissima (White Snakeroot) is highly toxic to humans and horses. Ingestion can cause severe symptoms, including weakness, nausea, abdominal pain, vomiting, delirium, cardiac damage, prostration, and, ultimately, coma. The toxic compounds, tremetone (a ketone) and glycosides, are present in all parts—flowers, leaves, roots, sap, seeds, and stems. Fatal if consumed. Poisonous flowers and plants: Identifying toxic risks around you