Companion plants for Geranium (Annual)
Geranium (Annual) blooms from May through October. It wants full sun and moderate water. The 8 companion pairings below each state why the pairing works.
Blooming before Geranium (Annual) opens

Yaupon Holly
Shares full sun and moderate water; blooms in mid spring, before this one opens; evergreen, so the bed keeps its shape through winter; its white flowers settle the red.

Chinese Fringe Flower
Takes full sun to part sun and moderate water; blooms in early spring, before this one opens; evergreen, so the bed keeps its shape through winter; taller at 8 ft, for the layer behind it.
Blooming alongside

Indian Hawthorn
Shares full sun and moderate water; opens in mid spring and overlaps into this one's season; evergreen, so the bed keeps its shape through winter; taller at 5 ft, for the layer behind it.

Swamp Sunflower
Shares full sun and moderate water; overlaps, then carries the display into late fall; its seed heads stand through winter, for structure and the birds; taller at 6 ft, for the layer behind it.

Ironweed
Shares full sun and moderate water; its seed heads stand through winter, for structure and the birds; taller at 5 ft, for the layer behind it.

Prairie Blazing Star
Shares full sun and moderate water; its seed heads stand through winter, for structure and the birds; taller at 3.5 ft, for the layer behind it.

Rosemary
Shares full sun and low to moderate water; opens in early spring and overlaps into this one's season; evergreen, so the bed keeps its shape through winter; taller at 3.5 ft, for the layer behind it.

Little Bluestem
Shares full sun and low to moderate water; its seed heads stand through winter, for structure and the birds; taller at 3.5 ft, for the layer behind it; orange sits close to red on the wheel.