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.


  1. With the early cold this year, Bidens mitis is one of the few plants still blooming here in northwest Florida in January.

  2. I am currently growing this species in our nursery. I think it has a lot of potential if used in the right spot

  3. Good to know. There have been times when I design a wetland mitigation project that I have wanted to use this. Used in large swaths, it is a beautiful addition to the wetland edge.

  4. Craig,
    I have a clump of this robust plant at the woodland edge in year-round mesic to seasonally moist soil with direct afternoon sun. It is in an ephemeral rainwater swale that has not accumulated any depth of water since last summer. The shrubby plant is clearly well-adapted though it has suffered extensive deer browsing (prompting a wire enclosure around the plant.) It seems to have not ceased to hold a sparse number of healthy blooms throughout the winter (and I think blooms have persisted through the several 2011 freezes here in N Pinellas). This is in a natural area with fierce competition for ground space, but I hope to see expansion. I am hoping that with enough numbers it can better withstand the deer browse, but perhaps that is just wishful thinking. Thanks for writing about this plant in your blog. It is fantastic. BWilkins

  5. Thanks for sharing this information - very interesting.

  6. Love this site, but I take offense at calling bidens alba "very weedy"'s all in your perspective! A weed is just a wonderful volunteer that wasn't planted, and we spend more time, effort and chemicals trying to eradicate them to have a hideous wasted expanse of decapitated, water hungry, useless grass! of LOL! Hey, this lovely little flower decorates my yard better than grass ever could, asks for nothing and provides free nutritious greens by just topping back the new growth, washing it well and cooking it in plenty of water for 15 minutes! Picking a cute little bouquet of the flowers every day or two keeps seeding in check (annoying stickers that they are) makes me smile and keeps the plants bushy and a productive source of food! It's a invaluable forage plant and more nutritious than most planted crops or anything you can buy. Change your perspective and LOL!

  7. Thanks for your post, CharGC, but no offense is given by calling something a weed. My wife likes to use a definition similar to yours, but in reality (and as a botanist) a weed is a plant with very specific characteristics - whether it is pretty/ugly - useful/obnoxious. Those characters include occurring in disturbed sites, producing large numbers of seed, spreading rapidly and often having a short lifespan. All the Bidens are "weedy", but they are good pollinator plants and aesthetically interesting. They do not play well with others, however, and do not mix well in a diverse wildflower landscape/meadow.


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