Is Black-Eyed Susan Toxic?
Few flowers are more instantly recognizable than the black-eyed Susan, with its egg-yolk-yellow petals and dark center disks. Closely related to the daisy, this wildflower is also called the brown daisy or the yellow ox-eye daisy. While this bright and cheerful flowering plant has never been found to be toxic to humans, it's better to leave them in the field or in a vase.
Tip
It is not advisable to eat any part of the black-eyed Susan plant. Though not considered poisonous, the plants can cause sensitive people allergic skin reactions and asthma attacks.
Meet the Black-Eyed Susan
The bright wildflower called black-eyed Susan (Rudbeckia hirta) has become a garden staple. Fast-growing and self-seeding, black-eyed Susan is well known for its daisy-like flowers with many thin petals and large, central seed heads. The leaves of the entire genus are hairy and scratchy, an adaptation to keep insects away.
If you don't have any growing in your yard, look for these flowers in the wild or along roadsides. Black-eyed Susan is native to the central United States and can be found in most parks in the Midwest.
Grow Black-Eyed Susans
Anyone with a wildflower garden will want to consider adding black-eyed Susans to their landscape. Keep in mind that different cultivars grow to different heights. The species plant grows to over 3 feet tall, with 6-inch leaves and 3-inch flowers. The large, "happy" blossoms attract butterflies, bees, and other beneficial insects.
These flowers bloom the full season from June to October if planted within their growing area, U.S. Department of Agriculture plant hardiness zones 3 through 9. They prefer a sunny location and well-drained soil. They are native plants, so require little to no fertilizer or fuss.
Appreciate Health Risks
There is no evidence that black-eyed Susan flowers or plants are toxic or poisonous to humans when ingested. The plant has a disagreeable taste which would certainly discourage snacking on them. However, these wildflowers have been known to be slightly toxic to cattle and pigs that eat them.
Currently, there is also no evidence that the flowers can poison humans when swallowed, but they have been known to poison grazing animals. Black-eyed Susans can, however, be toxic to cats when consumed.
Anyone with a known allergy to these plants should stay away. Even absent an allergy, the hairy leaves of the black-eyed Susan can irritate skin and cause redness and even blistering.