Zone: 4 to 8
Soil: sand to clay
Light: Full sun to part sun
Bloom colour: Purple
Bloom period: August to September
Height: 4 to 10 feet
Moisture:Usually medium to moist
Attracts: A variety of bees and butterflies.
Notes:The members of this genus are widely available at nurseries
Vernonia is a late season plant. It takes so long to emerge that you may well think it has died during the winter. Give it at least until the beginning of June. These plants are moderately attractive to bees and butterflies. Two species are native to Ontario. Vernonia missurica and Vernonia gigantea. A third species, Vernonia noveboracensis, is also native to the North East, but not in Canada. Typically this genus does well in average to moist soil. New York Ironweed can handle clay and a fair amount of shade. It grows up to 10 feet in height.
The Canadian species mentioned are similar in appearance and grow to about 5 to 6 feet high. They can hybridise. Missouri Ironweed is the more attractive of the two Canadian species while Giant Ironweed is more shade tolerant. Both species show some drought tolerance. The flowers are all deep purple in colour and are located at the top of the plant. Since the leaves are not outstanding in any way, it is better to plant them at the back of the border behind other plants.