Not heterophyllus - is it venustus?

[Broekhuis]

In my continuing saga of mis-ID'd penstemons, here's the offspring of some seed (not from the NARGS exchange) labeled P. heterophyllus. I grew that one before, and am pretty sure this is something different. It resembles the P. venustus I grew more recently, although these new plants are bigger; they were evergreen (or greened up early in spring) in my zone 6 garden, and tended to lay themselves down, rooting along the stem. I like it.

[Todd Boland]

If not venustrus is could be serrulatus...I grow that one and it looks quite similar to your photo.

[Nold]

Venustus. Serrulatus has smaller flowers.
This is one of my favorites.