This native wildflower grows as a biennial or short-lived perennial and produces numerous attractive flowers. The Philadelphia fleabane is a member of the aster family. Members of this large plant family produce a composite flower made of individual disc flowers and/or ray flowers (florets) that resemble petals.

There are three species of fleabane that bloom close to the same time in our state. The common or Philadelphia fleabane, the Eastern daisy fleabane (E. annuus) and the daisy fleabane (E. strigosus). The flowers appear almost identical, with the differences mostly in the form and attachment of the leaves. The Philadelphia fleabane has alternate stem leaves that are either not toothed or lightly toothed. These stem leaves clasp the stem at their base, a key identification trait for this species. Basal leaves are hairy and up to six inches long and have wide, rounded teeth. The stem is hairy. These basal leaves may disappear as the flowering stem begins to grow.

The Philadelphia fleabane starts to bloom in mid-spring (the earliest of the three species) and each flower head has 50-300 white ray flowers around yellow disc flowers. Sometimes there is a hint of pink in the ray flowers, especially as they first open. The flowers close during the night. The plant may continue to produce flowers for a month or a month and a half. The fruit is an achene that has a tuft of hair to allow wind distribution of the seeds.

Philadelphia fleabane is widespread across North America, growing in fields, along roadsides and on stream banks, but they prefer more moisture than the other two species. They will, however, adapt to drier locations with reduced size. Their common name comes from the belief that dried flowers of this plant could be used to rid a house of fleas. There is no evidence that it works for this purpose, though there are other aromatic plants, especially mints, which can repel insects. As a native plant, the fleabane species attract insects as pollinators a number of butterfly and moth species feed on the leaves.