Bur-Marigold Beauties

     Bur-marigolds bloom each year during the first few weeks of September here in Lancaster County, Pennsylvania.  This plant, Bidens laevis, grows up to three feet tall in sunny, wet habitats, often in clumps of itself.  Each plant has several cheery, yellow flowers that are about two inches across.  And each bloom has eight petals around a golden disc.
     The beautiful bur-marigolds are native to the United States from New England south to the Gulf of Mexico, across to Mexico and in much of South America.  This species is mainly coastal, but spotty inland.  Here in Lancaster County they are absent from most wet habitats, but abundant where they have become established.  They develop colonies of themselves along both shores of streams and brooks in sunny cow pastures.  The attractive sneezeweeds, spotted jewelweeds, arrowheads and other plants of wet habitats often are the associates of bur-marigolds.  These flowering plants usually don't get mowed because they grow from mud close to waterways.  Mowers are likely to get stuck in the mud.           
     Bur-marigolds are not only pretty in themselves, but also in the multitudes of insects they attract.  Insects of several kinds are all over those blossoms, making them more interesting.  Those insects are there to sip sugary nectar and eat pollen, fertilizing the blossoms in the process.  Cabbage white butterflies are particularly abundant around bur-marigold flowers in this area, followed by yellow sulphur butterflies.  Some other kinds of butterflies I've seen on them in September include pearl crescents, buckeyes, silver-spotted skippers and monarchs. 
     Monarch butterflies at this time of year are those that will make the trip to certain forests on mountains in the middle of Mexico, forests where they will spend the northern winter in comparative warmth.  I've seen several monarchs at a time sipping nectar from bur-marigold blooms, and other kinds of flowers, to get energy for their trip southwest.  The lovely monarchs on the pretty bur-marigold blooms are beauty enough in themselves.  Probably, monarchs need to sip nectar every day along the way of their migrations.  
     Other types of insects I have seen on bur-marigold flowers are digger wasps and bees, particularly bumble bees.  Digger wasps have black bodies and brown-orange abdomens.  The adults sip nectar from flowers, but their young eat the larvae of green June beetles their mothers paralyze with a sting and bury in the ground.  Each female digger wasp lays one egg on top of each paralyzed beetle larva.  The wasp larva eats its host, the beetle larva, pupates in the soil and later emerges as an adult wasp.
       Bur-marigolds are also called beggar ticks because their seeds are two-pronged, with sharp points and tiny barbs on those small prongs.  Because of those barbs, the seeds cling to the fur of animals and peoples' clothing and are carried away from the parent plants.  If those irritating seeds are pulled out of fur and clothing in damp habitats, a new colony of bur-marigold plants may develop.  Some of those seeds are eaten by rodents and small, seed-eating birds, however.
     Look for patches of blooming bur-marigold plants in moist, sunny habitats at this time of year.  They are lovely and cheery, and provide food for a variety of wildlife, which adds to their beauties and intrigues.