Common or Philadelphia Fleabane

Erigeron philadelphicus

The genus Erigeron is a large, diverse genus.  There are 340 species worldwide.  Western North America is the center of its diversity, with 173 species in North America.  Four species have been reported in Wildwood Park.  Three of them are similar and are known as fleabanes; the fourth is known as Robin's plantain.  The word bane is an archaic word meaning poison.  Thus fleabanes supposedly kill or repel fleas.  There is no evidence however that dried fleabane bothers fleas in the least.

Erigeron is in the Asteraceae or Sunflower Family.  Like daisies, sunflowers, and our very first Species of the Week, the prairie ragwort, members of this genus have two kinds of flowers.  What most people call the flowers are actually flower clusters called heads.  As can be seen from the pictures below, the center of each fleabane head is a little button made up of many tiny, yellow, trumpet-shaped flowers called disc flowers.  Surrounding these are many ray flowers, which have a single, long white petal.

Common fleabane is indeed very common in Wildwood in the late spring. It can be found in patches in the woods on the east side, in sunny areas along trails, and all along the Riverway bikepath, as in the picture above.   It has 100-150 ray flowers, white, or sometimes pinkish.  The stem leaves clasp the stem, meaning the leaf blade reaches around past the stem in two small finger-like projections.  This can be seen in the pictures below, but is not clearly obvious.  The plant is quite variable in how big it gets, how many flower heads it produces, and how many leaves it has, depending on its habitat.  Compare the plants shown in the pictures below.

Daisy fleabane, Erigeron annuus, and lesser daisy fleabane, Erigeron strigosus, bloom later, in the summer.  They have fewer rays and smaller flowers and their leaves do not clasp the stems.  Robin's Plaintain has larger flower heads with pink or blue rays.

Common fleabane and the summer-blooming fleabanes are weedy plants, which means they thrive in disturbed places like roadsides, trailsides and vacant lots, not to mention gardens.  This is why so many line the Riverway.  Although they are weedy plants, they are not aliens.  All four species of Erigeron in Wildwood are natives of eastern North America.   Common fleabane has spread outside its native habitat and is now an annoying weed worldwide.  This illustrates the fact that even the most noxious alien exotic was a native somewhere before it hitched a ride with humans to a new location.

Common fleabane is very common in early summer, but it will be replaced by the daisy fleabanes which will keep on blooming all summer, often until frost.  In the summer they will be joined by true daisies, and in the fall by asters (see smooth aster and heartleaf aster from fall 2006 Species of the Week).  All of these plants look similar, with white rays around the central yellow button.  Look for fleabane now just about everywhere in Wildwood, and look for it also along roadsides and in your garden.  These plants may be weeds, but they are truly native American weeds.

GGC