Companion plants for Snow-in-Summer
Snow-in-Summer blooms from May through June. It wants full sun and low water. The 8 companion pairings below each state why the pairing works.
Taking over as Snow-in-Summer finishes

Butterfly Bush
Shares full sun and low water; overlaps, then carries the display into early fall; stands well above at 6.5 ft, a canopy to plant beneath; a soft color beside the white.

Obedient Plant
Shares full sun and low to moderate water; blooms in late summer, extending the bed's season; stands well above at 3.5 ft, a canopy to plant beneath; a soft color beside the white.

Potentilla
Shares full sun and low water; overlaps, then carries the display into early fall; taller at 3 ft, for the layer behind it; a soft color beside the white.

Bee Balm
Shares full sun and low to moderate water; blooms in midsummer as this one finishes; taller at 3 ft, for the layer behind it; a soft color beside the white.

Hybrid Tea Rose
Shares full sun and low to moderate water; overlaps, then carries the display into mid fall; stands well above at 4 ft, a canopy to plant beneath; a soft color beside the white.

Maiden Grass
Shares full sun and low water; blooms in early fall, extending the bed's season; stands well above at 6 ft, a canopy to plant beneath; a soft color beside the white.

Russian Sage
Shares full sun and low water; blooms in midsummer as this one finishes; stands well above at 4 ft, a canopy to plant beneath; a soft color beside the white; this one spreads, so it will crowd its neighbor in time.
Blooming alongside

Forsythia
Shares full sun and low to moderate water; blooms in early spring, before this one opens; stands well above at 6.5 ft, a canopy to plant beneath; a soft color beside the white.