Should I bring this years Penstemon plants in for the winter?

Question

We don’t get bad frosts here as we are only a mile from the sea.

Answer 1

If they are in pots they will be more vulnerable to cold so would be best brought in to an unheated conservatory or greenhouse. If in the ground they would probably be OK left out, although penstemons do vary slightly in hardiness, depending on the species. A specialist grower could supply more information. As a precaution, you could mulch the crowns with a thick layer of leafmould or compost over the winter.