One of the best late, blue-blooming perennials, it looks like a tall Annual Ageratum. White-flowered 'Alba' is also available. Can be invasive. Leaf miner is a problem. Plant with Asters and Chrysanthemums.
Attributes - Eupatorium coelestinum
Plant Type: Perennial
Bloom Season: Late Summer through Mid Fall
Flower Color: Blue
Height: 1 ft. to 3 ft.
Width: 2 ft.
Sunlight: Full Sun, Partial Sun
Climate: Zones 5, 6, 7, 8, 9
Notes: Thrives in Wet Soil. Cut Flowers. Susceptible to Aphids, Powdery Mildew.