Fields of yellow flowers can be found all over the state. Issues with cressleaf groundsel can bring about questions concerning toxicity to livestock. Previous C.O.R.N. articles have covered management and can be found here. Cressleaf groundsel may be confused with members of the mustard family, or other species with yellow flowers that bloom this time of year. Below are some key ID characteristics and pictures that can be helpful in differentiating cressleaf groundsel from other species.
Cressleaf groundsel, or butterweed (Packera glabella)
Leaves – alternate, divided leaves with round-toothed lobes
Stems – smooth and hollow
Flowers – clusters of ray flowers
Picture credit: Curtis Young
Hedge mustard (Sisymbrium officinale)
Leaves – deeply divided leaves, triangular shape
Stem – hairy stem
Flowers – four petals per flower
Picture credit: Sam Custar
Yellow rocket (Barbarea vulgaris)
Leaves – alternate leaves with large terminal lobe
Stem – hairless stem
Flower – four petals per flower
Picture credit: Bruce Ackley (1 & 2) and Doug Doohan (3)
Lesser celandine (Ranunculus ficaria)
Leaves – kidney to heart shaped
Stem – basal rosette
Flower – 7 to 12 yellow petals
Picture credit: Joe Boggs