Penstemon heterophyllus Electric Blue is a low-growing variety with multiple spikes of impressive electric blue flowers that are tinged with pink before opening fully. It is great for adding colour right through the autumn, and will benefit from regular picking. Its narrow, lance-shaped leaves are bluish-green and semi-evergreen.

A favourite cottage garden plant since Victorian times, Penstemons have large bell-shaped flowers in tapering spires on mid-height stems, rather like a smaller version of the foxglove. These vigorous perennials are drought tolerant and fairly hardy.

Let it grow up through other plants and grasses in the border, which act as supports to this sometimes rangy plant. Pair with deep purples and blues, or try planting with architectural grasses or rich-coloured sedums for an impressive garden display.