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

Pansy
Takes full sun to part sun and moderate to high water; blooms in early spring, before this one opens; low at 8 in, to carpet the ground beneath; both offer pollinator forage, in different months.

Tulip Tree
Shares full sun and moderate to high water; blooms in late spring, before this one opens; both offer pollinator forage, in different months.

English Daisy
Shares full sun and moderate to high water; blooms in mid spring, before this one opens; low at 6 in, to carpet the ground beneath; both offer pollinator forage, in different months; they only overlap in zones 7 to 8.
Taking over as Canna Lily finishes

Winterberry
Shares full sun and high water; blooms in mid fall as this one finishes; both offer pollinator forage, in different months; echoes the red.

Sweet Alyssum
Shares full sun and moderate to high water; low at 5 in, to carpet the ground beneath; overlaps, then carries the display into mid fall; both offer pollinator forage.

Autumn Crocus
Shares full sun and moderate to high water; overlaps, then carries the display into mid fall; low at 6 in, to carpet the ground beneath.
Blooming alongside

White Clover
Shares full sun and moderate to high water; opens in late spring and overlaps into this one's season; low at 4 in, to carpet the ground beneath; both offer pollinator forage.

Gardenia
Takes full sun to part sun and high water; opens in late spring and overlaps into this one's season; evergreen, so the bed keeps its shape through winter; its white flowers settle the red.