Here is another easy plant for all gardeners who like purple. Vernonia noveboracensis (pronounced ver-NOH-nee-ah no-vee-bor-ah-SEN-sis), “New York Ironweed” is ideal for hot, humid climates. Please don’t confuse this one with Veronica, a totally different plant.
Ironweed is tall and narrow. It has large clusters of tiny purple flowers mid-summer to late fall. The flowers attract butterflies and bees, so it is perfect for the back of a pollinator garden. It blooms best in full sun, but will also tolerate half-sun. If the spent blooms are pruned away, the plant frequently will branch and re-bloom. If you forego the deadheading, finches and other seed-loving birds will visit to remove the seeds for you. Mine have occasionally reseeded. Baby plants are easy to relocate.
Ironweed prefers an acidic soil, so don’t bother with lime. They like moist soils that are high in organic matter, but will tolerate less water. Mine are planted in heavy clay soil and do well. The plant’s tolerance for varying moisture levels means it will do well in rain gardens.
Left alone, Ironweed will reach 6 to 8 feet in height. This is a little too tall to fit into the garden beds in the Mary Snoddy garden, so I cut it back by half in mid-May. This delays the flowering a bit, but the plant branches where it is cut back, so I end up with more flowers than if I had left it unpruned. The brilliant purple blooms pair well with most other colors. In this year’s annual bed, I grouped it with Melampodium, a wonderful annual that I will write about next week.
Ironweed dies completely to the ground in freezing weather. The dead stems should be pruned off. It is perennial in most of the US (zones 5a to 9b). This one looks equally at home in mixed borders and wildflower plantings. Highly recommended!