However, it can become problematic in agricultural fields, forestry regeneration sites, and disturbed areas. Typically to 2 m tall, rarely to 6 m in moist fertile soils. Infestations can be noxious , but seldom persist in California. Introduced from the Central and Eastern U.S., where it is often troublesome in agricultural fields and drainage areas. Subsequent leaves deeply pinnate-lobed, sparsely covered with short, white or gray, bristly hairs.
First leaves ovate to lanceolate, slightly coarse-lobed.
Subsequent leaves opposite, coarsely 3-lobed. First and subsequent leaves moderately covered with stiff hairs. Foliage covered with white to gray, short, bristly hairs. Leaves often opposite near the stem bases, alternate on the upper stems , gray-green, bipinnately lobed , with the primary lobes deep, to 8 cm long and 7 cm wide. Stems coarse, single or branched, woody at the base, longitudinally black-lined, covered with soft to bristly hairs.