Companion plants for Passionflower
Passionflower blooms from July through September. It wants full sun and moderate water. The 8 companion pairings below each state why the pairing works.
Blooming before Passionflower opens

False Indigo
Shares full sun and low to moderate water; blooms in late spring, before this one opens; both are strong pollinator plants, and they feed in different months; its seed heads stand through winter, for structure and the birds.

Chives
Shares full sun and moderate water; blooms in late spring, before this one opens; both are strong pollinator plants, and they feed in different months; echoes the purple.

Lupine
Shares full sun and moderate water; blooms in late spring, before this one opens; both are strong pollinator plants, and they feed in different months; lower at 3 ft, for the front of the border.

Weigela
Shares full sun and moderate water; blooms in late spring, before this one opens; both are strong pollinator plants, and they feed in different months; lower at 5 ft, for the front of the border.

Tulip Tree
Shares full sun and moderate water; blooms in late spring, before this one opens; both are strong pollinator plants, and they feed in different months; yellow against purple, for contrast.

Mock Orange
Shares full sun and moderate water; blooms in late spring, before this one opens; both offer pollinator forage, in different months; lower at 8 ft, for the front of the border.
Taking over as Passionflower finishes

Aster
Shares full sun and moderate water; overlaps, then carries the display into mid fall; both are strong pollinator plants; its seed heads stand through winter, for structure and the birds.

Winterberry
Shares full sun and moderate to high water; blooms in mid fall as this one finishes; both are strong pollinator plants, and they feed in different months; lower at 6.5 ft, for the front of the border.