What Are the Moisture Requirements for penstemon 'Windsor Red'?
Moist but well drained

penstemon 'Windsor Red' · Penstemon 'Windsor Red'
Grow in fertile, moist but well-drained soil in full sun or light shade in a position sheltered from frosts and drying winds; in autumn, cut plants down by two-thirds of their height and protect with a dry mulch; for more advice, see penstemon cultivation
Moist but well drained