Companion plants for Dead Nettle
Dead Nettle blooms from May through July. It wants part shade and moderate water. The 8 companion pairings below each state why the pairing works.
Blooming before Dead Nettle opens

Tall Oregon Grape
Shares part shade and moderate water; blooms in early spring, before this one opens; stands well above at 4.5 ft, a canopy to plant beneath; both offer pollinator forage, in different months.

Hellebore
Shares part shade and moderate water; blooms in late winter, before this one opens; evergreen, so the bed keeps its shape through winter; taller at 1.5 ft, for the layer behind it.
Taking over as Dead Nettle finishes

Zigzag Goldenrod
Shares part shade and moderate water; blooms in late summer as this one finishes; both offer pollinator forage, in different months; its seed heads stand through winter, for structure and the birds.

Northern Sea Oats
Shares part shade and moderate water; overlaps, then carries the display into early fall; taller at 3.5 ft, for the layer behind it; its seed heads stand through winter, for structure and the birds.

Blue Wood Aster
Shares part shade and moderate water; blooms in late summer as this one finishes; both offer pollinator forage, in different months; its seed heads stand through winter, for structure and the birds.
Blooming alongside

Pinxterbloom Azalea
Shares part shade and moderate water; opens in mid spring and overlaps into this one's season; stands well above at 5.5 ft, a canopy to plant beneath; evergreen, so the bed keeps its shape through winter.

Drooping Leucothoe
Shares part shade and moderate water; taller at 4 ft, for the layer behind it; evergreen, so the bed keeps its shape through winter; both offer pollinator forage.

Western Sword Fern
Takes part shade to full shade and moderate water; taller at 3.5 ft, for the layer behind it; evergreen, so the bed keeps its shape through winter.