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

Summersweet
Takes part shade to full shade and moderate to high water; blooms in midsummer, extending the bed's season; stands well above at 6 ft, a canopy to plant beneath; its white flowers settle the white.

Goatsbeard
Takes part shade to full shade and moderate water; blooms in early summer as this one finishes; taller at 4 ft, for the layer behind it; its white flowers settle the white; this one spreads, so it will crowd its neighbor in time.

Rhododendron
Takes part shade to full shade and moderate water; overlaps, then carries the display into early summer; stands well above at 6 ft, a canopy to plant beneath; a soft color beside the white.

Lady's Mantle
Takes part shade to full shade and moderate water; overlaps, then carries the display into midsummer; taller at 1.5 ft, for the layer behind it; a soft color beside the white.

Ligularia
Takes part shade to full shade and moderate to high water; blooms in midsummer, extending the bed's season; taller at 4 ft, for the layer behind it; a soft color beside the white; this one spreads, so it will crowd its neighbor in time.

Northern Sea Oats
Takes part shade to full shade and moderate water; blooms in midsummer, extending the bed's season; taller at 3.5 ft, for the layer behind it; a soft color beside the white; this one spreads, so it will crowd its neighbor in time.
Blooming alongside

Ostrich Fern
Takes part shade to full shade and moderate to high water; taller at 4 ft, for the layer behind it.

Camellia
Takes part shade to full shade and moderate water; blooms in midwinter, before this one opens; stands well above at 6.5 ft, a canopy to plant beneath; a soft color beside the white; they only overlap in zones 7 to 8.