Dog fennel is a native of the eastern, especially southeastern, United States. Like
“real” fennel, dog fennel has feathery leaves, and crushed leaves smell strongly.
It is found on roadsides, in
flatwoods, marshes, and disturbed areas. Most consider it a weed.
Plants: 1½-6½′ (50-200 cm) tall, erect, with several
forked stems. Stems are round, light green or reddish to dark red or purple, and finely hairy.
Stems are soft when young, becoming woody and tough later.
Leaves: Leaves are finely divided and needle-like. When
crushed, they produce an unpleasant odor.
Flowers: A profusion of tiny, inconspicuous greenish-white
flowers 1/16-⅛″ (2-3 mm) long appear all over the upper segments of the plant. Flowers appear from June to November.
A scarlet-bodied wasp moth nectaring on buttonbush. The moth eats dog fennel shortly before mating, using the plant’s toxins for the defense of himself and his mate.
Edibility: Poisonous Dog fennel produces toxic
pyrrolizidine alkaloids to protect itself from insects. Though not intensely poisonous, forage animals can be
sickened. Scarlet-bodied wasp moths eat dog fennel, absorbing these toxins and using them
to protect their mates.