Companion plants for Ranunculus
Ranunculus blooms from April through May. It wants full sun and moderate water. The 8 companion pairings below each state why the pairing works.
Taking over as Ranunculus finishes

Feather Reed Grass
Shares full sun and moderate water; blooms in early summer as this one finishes; leafs out to hide the ripening bulb foliage as it dies back; its seed heads stand through winter, for structure and the birds; they only overlap in zones 8 to 9.

Blanket Flower
Shares full sun and low to moderate water; blooms in early summer as this one finishes; leafs out to hide the ripening bulb foliage as it dies back; orange sits close to pink on the wheel.

False Indigo
Shares full sun and low to moderate water; leafs out to hide the ripening bulb foliage as it dies back; overlaps, then carries the display into early summer; its seed heads stand through winter, for structure and the birds; they only overlap in zones 8 to 9.

Blue Oat Grass
Shares full sun and low to moderate water; blooms in early summer as this one finishes; leafs out to hide the ripening bulb foliage as it dies back; evergreen, so the bed keeps its shape through winter; they only overlap in zones 8 to 9.

Pampas Grass
Shares full sun and low to moderate water; blooms in late summer, extending the bed's season; its seed heads stand through winter, for structure and the birds; stands well above at 8.2 ft, a canopy to plant beneath.

Gardenia
Takes full sun to part sun and moderate to high water; overlaps, then carries the display into midsummer; evergreen, so the bed keeps its shape through winter; taller at 3.9 ft, for the layer behind it.

Sunflower
Shares full sun and moderate water; blooms in midsummer, extending the bed's season; its seed heads stand through winter, for structure and the birds; taller at 6.6 ft, for the layer behind it.
Blooming alongside

Agave
Shares full sun and low to moderate water; leafs out to hide the ripening bulb foliage as it dies back; evergreen, so the bed keeps its shape through winter.