Last spring, the good people at the American offshoot of Blooms of Bressingham sent us some new penstemons to try. One of them, 'Prairie Delight', is (as Brits used to say) in its pomp at the moment – that is, it's looking wonderful. The others are dead. Let me tell you more.

Penstemon 'Prairie Delight' is a lovely thing. Created by the world's top penstemon expert, Dr. Dale Lindgren at the University of Nebraska where, believe me, it gets cold in the winter, it combines the blood of at least three different American native species - P. brevisepalus, P. gentianoides and P. parryi - although it seems there may be a little from other species in there somewhere as well.

Its spring rosettes are strongly red-tinted so you know you have something interesting right from the start and then by early June it's sent up these red-tinted vertical stems… Well, you can see from the pictures (click to enlarge) how pretty the flowers are. We have it in three different spots, as long as it gets plenty of light it seems to thrive.

Contrast that with the four others we tried, all penstemons in the more flamboyant British style and none worth growing here: 'Sweet Joanne', 'Pensham Amelia Jayne', 'Pensham Elanor Young' and 'Pensham Czar' (below, click to enlarge). These have larger flowers, at their best (that would be in Britain) they're more dramatic, they're more juicy in their growth, they start to flower later, they continue for longer - and here in Pennsylvania they're all dead. What's worse, only two of them flowered at all last year, 'Pensham Amelia Jayne' and 'Pensham Czar', and those two were very sparse.

To be fair, I know the winters are too cold for them here. But I expected a really colorful display in their first and only summer. We put some in a large container in a really sunny spot, the others went in a new bed that gets at least half a day's sun. They grew well, but even those that flowered were not impressive – spindly and sparse.

I look forward to trying 'Prairie Delight' back in England, perhaps it will be as good as it is here in Pennsylvania or perhaps it will be poor. The others I know do well back in Britain, I've seen them looking superb.

And that's the thing: until you actually grow them you never know. The nurseries will tell you they're wonderful, but you never know till you try. That's why it's so valuable that growers like Blooms of Bressingham send out new plants for people like me to assess. I grow them, I take note. And, although I don’t always write them up as I have done here, growing them will inform my writing about them for years. 'Prairie Delight' is going straight into my new plants lecture.