Thrived in Zone 5b/6a through every weather
"This is one of the first plants I chose for my purple & orange themed perennial garden. It is THRIVING. The garden is a weird one: along the driveway, south & west facing, retaining wall. Good drainage, punishing heat; slight slope so one end of the garden is mesic, and the other end is more xeric. Soil is what I would describe as loamy, leaning towards sandy loam. This plant handles both ends of the soil moisture and temperatures spectrum with equanimity. We've had Arctic cold (-25F wind chill!) with no insulating snow cover; we've had droughts. We've had record snowfall. This penstemon has toughed it out and just keeps blooming beautifully by the footpaths. It's been such a boon to our wild bee friends. If planting in loamy soils, I recommend planting White Horehound near it. Bees use it as medicine!"