Spires of tubular flowers of blue, stained purple, help Penstemon ‘Stapleford Gem’ stand out in the garden. The flowers share a pout with the thicker petals of foxgloves, but have more of a luminescent quality. Purple beelines draw our eyes down the pale throat into the flower.
Some very reputable UK nurseries are selling this plant by the name of Penstemon ‘Sour Grapes’ but the RHS advises us that this is a misnomer.
Shared for Cee’s Flower of the Day
Susan Rushton 
You make me discover this amazing flower. Blue is my favorite color, I like it! Thank you, Susan!
I love blue in the garden too.
Is this a cultivar of a Californian species? I can not keep them all straight.
The full name is Penstemon × gloxinioides ‘Stapleford Gem’ but my knowledge of what is a Californian species is significantly less than yours!
Most of my knowledge about such matters is not accurate. Those who develop it will say what they want about it to sell it. It is weird that those in other regions, even Australia and New Zealand, know more about some cultivars of Californian species than we do in California.
Beautiful – it’s my favourite penstemon. (And it’s great to know the correct name so that I can buy a replacement for the plant I had years ago. 🙂 )
Perhaps it is a case where you might want to see the plant in flower before you take the plunge, just to be on the safe side. 🙂
Mind you, if you’re like me, you’ll probably like them all, just to a greater or lesser degree.
That’s the problem for me…I like too many and haven’t the space for all of the plants I’d like!