What to Know: This perennial weed spreads by seeds and a migrating ... and southern Canada. ID It: Serrated five-lobe leaves on wiry stems; small yellow flowers in late spring and early summer.

Barnyard grass is a vigorous, warm season annual grass reaching 1 to 5 feet ... other weeds but are weak on nightshade. Canada goldenrod is a perennial growing to heights of 4 feet. spreading by ...