A large genus of around 290 species from the Americas. Shrubs, mainly from Mexico and S. America, and herbaceous species from N. America. Opposite leaves and flattened clusters of white to pink flowers. Both sometimes scented. Few are grown in the UK, but those that are, the foliage can be the most attractive feature. Some previously known as Eupatorium.
The tiny but numerous flowers that make up the flower heads contain nectar and pollen that attracts a range of insects including butterflies, flies and bees.