Penstemons are valued for their weeks of interest in borders and rock gardens. As a rule, rock garden penstemons are reliably hardy, provided they are given good drainage and a sunny spot. Border types may be killed in cold or wet winters. With these, it is best to take cuttings in late summer and overwinter them in a frost-free greenhouse in case of loss.
Following trials at Wisley, the Award of Garden Merit was given to 20 tall border cultivars and six dwarf rockery types.
Here are a few of the best for the border;
- Create a cottage garden look with pink and white Penstemon 'Osprey' AGM (height 1m (39in)) or pale mauve P. ‘Alice Hindley’.
- Blues and purples are well represented with lilac-purple P. 'Stapleford Gem' AGM (height 75cm (30in)) and the wonderfully named P. ‘Sour Grapes’.
- In the hot border, grow the tall (1m (39in)) P. 'Rubicundus' AGM with its large scarlet, white-throated blooms or crimson-flowered P. 'Schoenholzeri' AGM.
- The rich, sultry purple of P. 'Raven' AGM is set off by the white throat. Height 1m (39in).
- Of the white forms, P. 'White Bedder' AGM gives a beautiful show. Height 60-70cm (24-27in).
And for the rockery;
- P. rupicola AGM – a glaucous-leaved, creeping evergreen, just 6cm (2½in) tall, bearing delicate, rose-pink flowers.
- Slightly taller at 15cm (6in), P. newberryi AGM is another evergreen with deep rose-pink flowers.
- The more upright P. fruticosus var. scouleri AGM has light purple blooms and reaches 30cm (12in). There is also a white flowered form.
Further information
Find a nursery that stocks these Penstemon cultivars in the online Plant Finder.
Helen Bostock