That's also one Penstemon species which I soon lost, Karen, in my case even a year or two after planting; all our Penstemon were purchased as plants in flower.
Several on-line sources do say that P. smallii only lasts 2 to 3 years (in gardens), especially in fertile soils (e.g. below).
By now, I must have planted over two dozen Penstemon species (including named cultivars) and hybrid Penstemon cultivars and have had only five survive more than 2 to 3 years. Happily, however, those five have been long-term survivors.