Companion plants for Penstemon
Penstemon blooms from June through August. It wants full sun and low water. The 8 companion pairings below each state why the pairing works.
Blooming before Penstemon opens

Candytuft
Shares full sun and low water; blooms in mid spring, before this one opens; both are strong pollinator plants, and they feed in different months; evergreen, so the bed keeps its shape through winter.

Blue Princess Holly
Shares full sun and low to moderate water; blooms in mid spring, before this one opens; both are strong pollinator plants, and they feed in different months; evergreen, so the bed keeps its shape through winter.

Rock Cress
Shares full sun and low water; blooms in mid spring, before this one opens; both offer pollinator forage, in different months; evergreen, so the bed keeps its shape through winter.

Electric Lights Red Azalea
Takes full sun to part sun and low to moderate water; blooms in mid spring, before this one opens; both are strong pollinator plants, and they feed in different months; evergreen, so the bed keeps its shape through winter.
Taking over as Penstemon finishes

Pink Muhly Grass
Shares full sun and low water; blooms in early fall as this one finishes; both are strong pollinator plants, and they feed in different months; its seed heads stand through winter, for structure and the birds.

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

Switchgrass
Shares full sun and low 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.
Blooming alongside

False Indigo
Shares full sun and low water; opens in late spring and overlaps into this one's season; both are strong pollinator plants; its seed heads stand through winter, for structure and the birds.