Sunday, January 9, 2011
Burr Marigold - Bidens laevis
Burr marigold (Bidens laevis) is a member of a genus best known for the very weedy, Spanish needles (Bidens alba). All members share similar characteristics: they are annuals that produce flowers especially valuable to pollinating insects and seeds that have needle-like appendages that "stick" to clothing and animal fur. They are, therefore, wonderful additions to a wild butterfly/bee landscape, but a horrid nusiance to landscapes where we might spend time walking through.
Burr marigold is not a plant for small gardens, but an exquisite addition to an expansive wetland planting where it can spread and produce large swaths of bright yellow flowers in the very late fall and early winter. It occurs statewide in Florida and throughout much of the Deep South to Texas in wet soil habitats. It prefers marshes and river flats, but can grow in a great many locations if given at least partial sun.
Like other members of this genus, it persists and spreads over time by producing large numbers of seed. These seeds can be important food sources for some songbirds, but the real wildlife value comes from its use as a nectar source for bees and butterflies. Patches of burr marigold bloom heaviest in November and early December and well-established plantings may contain thousands of flower heads at any one time.
Individuals reach about 3 feet tall at flowering time. They are weakly stemmed with numerous short side stems.
If you have an area around a pond or stream, add this in locations that stay moist and frequently flood to about 6-12 inches during high water. You don't need much as it will spread throughout suitable habitat. This species is infrequently offered by commercial sources that specialize in wetland mitigation plantings. We do not grow it at Hawthorn Hill, but admire its beauty in the natural areas we hike and explore each late fall.