Patience!
"I’m pleasantly surprised with the first blossoming of my Penstemon Davidson. I planted it spring of 2024 and it never flowered. I emailed high country last year and was told they were surprised the plants survived at all, being in CT. I was thinking to dig it out this year…so glad it didn’t!! I’m in zone 7, with somewhat sandy soil, full am sun and afternoon shade. Basically what is recommended. So, I recommend this pretty plant and will mention to just be patient. (Idk who I spoke with, but they didn’t read their own information) And the slew of rabbits who scuttle throughout the neighborhood haven’t touched it!"