Spotlight on: Penstemons 

If you’re looking at your border in late summer and need to add some instant colour, Penstemons are the answer. Plant in groups of three or five for impact. Most border types will continue to flower up until the first frosts. 

Penstemons can be divided into roughly two types. Border hybrids, which grow to between 60 and 80cm and are very colourful, with foxglove-like flowers, and species Penstemons which are usually lower growing with smaller flowers. Nearly all originate from North America. Border hybrids tend to flower from June to October and species for a shorter period, earlier in the season. 

There are many varieties available and all are bright and colourful and liven up a late-summer border. They thrive in a sunny spot in well-drained soil. 

It used to be thought that Penstemons were tender and needed protection from frost, but actually they are one of the most valuable late summer-flowering perennials and, in all but the very coldest regions, are easy, reliable and pest free. 

To prevent plants from failing to make it through winter, don’t cut faded stems back hard until spring. If the plant is a few years old and losing it’s vigour, take a few stem cuttings in autumn and you’ll have strong new plants in spring. 

Some Penstemons to try: 

Penstemon heterophyllus 'Heavenly Blue' - A woody dwarf Penstemon which forms a low mound absolutely smothered in summer in rich blue flowers. The flower colour is predominantly blue, but overlaid with tints of pink. Ideal for front of border or rockery situation. 

Penstemon 'Hidcote Pink' - A lovely Penstemon with rose-pink flowers, streaked with purple on the creamy-white throat. It seems to flower all summer and into autumn. 

Penstemon 'Sour Grapes' - One of the best border Penstemons. A smoky mixture of pink and blue with an almost metallic silver sheen on the back of the purple-streaked slender trumpets over much of the summer and into autumn. 

Penstemon pinifolius - Fiery red flowers above neat foliage make this a most desirable alpine. Ideal for rockeries, gravel gardens and pots. 

Penstemon pinifolius 'Mersea Yellow' - The yellow version of the more usual red flowered Penstemon. The foliage is a lighter green too.