5-6' x 24" wide, (seed propagated). Backyard bird watchers rejoice! This prairie wildflower has big, flat nutritious seeds in fall that are highly sought after by numerous song bird species. In late summer Silphium sends up tall bloom spikes covered with multitudes of large yellow daisies. Its large, deeply divided leaves typically orient themselves in a north-south direction (hence its common name Compassplant). This plant grows in all types of soils including heavy clay! Zones 4-8.