Robuta

https://www.rhs.org.uk/plants/344087/penstemon-digitalis-isa/details Penstemon digitalis 'Isa' | /RHS penstemon digitalis isa rhs https://www.rhs.org.uk/plants/520444/penstemon-digitalis-blackbeard/details Penstemon digitalis 'Blackbeard' | Herbaceous Perennial/RHS penstemon digitalis herbaceous perennial blackbeard rhs