Plants that bloom in October in Zone 6 with green flowers

Big Bluestem

The signature grass of the tallgrass prairie, turning copper-bronze in fall with distinctive turkey-foot seed heads.

Little Bluestem

Upright clumps turn coppery orange in fall and stand well through winter.

Northwind Switchgrass

Stiffly upright blue-green foliage that never flops. The most architectural switchgrass available.

Sedum

Succulent leaves, tough as nails. Ages to deep crimson in autumn.