This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Agrimonia mollis, Britton
Native. Perennial. Propagates by seeds and by tubers.
Time of bloom: July to October.
Seed-time: August to November.
Range: Connecticut to Michigan, southward to North Carolina and
Kansas. Habitat: Hillsides, dry woodland borders, and thickets.
Roots tuberous, rather thick and elongated. Stems very slender, two to five feet tall, with slim ascending branches, covered with fine, very soft hair. Leaflets five to nine (mostly seven), with two or three intermediate smaller pairs, oblong to elliptic or obovate, obtuse, rather thick, scallop-toothed, grayish green and very softly hairy on both sides; stipules oblong to lance-shaped, and entire, or sometimes broad and sharply toothed. Racemes long and wandlike, interrupted, the flowers nearly a half-inch broad, bright yellow.
Fig. 154. -Tall Hairy Agrimony (Agrimonia gryposepala).
The top-shaped burs about a quarter-inch long, the ring of hooked bristles ascending nearly in a single row.
If deprived of leaf growth by frequent cutting throughout the growing season, the tubers shrivel and die; in any case no fruits should be allowed to mature in the neighborhood of grazing flocks.