Plants that bloom in May in Zone 5 with green flowers

Bigtooth Maple

Mountain West maple with brilliant orange-red fall color and rugged drought tolerance.

Coral Bells

Grown mostly for dramatic foliage, but the tiny bell flowers are a bonus.

Jack-in-the-Pulpit

Hooded green-and-brown striped spathe sheltering a hidden spadix. Woodland curiosity followed by red berries.

Japanese Painted Fern

Silver and burgundy fronds unlike any other fern. Foliage plant that earns its keep on color alone.

Lady's Mantle

Chartreuse frothy flowers and pleated blue-green leaves that hold water droplets like mercury. The ultimate filler plant.

Ostrich Fern

Tall vase-shaped fronds that unfurl from fiddleheads in spring. Spreads to form dramatic colonies.

Paperbark Maple

Cinnamon-colored peeling bark and good fall color provide strong four-season interest.

Rhubarb

Huge leaves and thick red stalks give a lush look while supplying tart harvests.