Border penstemons are easy to grow in any fertile, reasonably moist, free-draining soil in full sun or light shade.
Planting is best done from mid- to late spring. Enrich the soil with about a bucketful of well-rotted organic matter and 70g per sq m (2oz per sq yd) of balanced general-purpose fertiliser to aid good establishment. Alpine and shrubby penstemons need relatively infertile soils, so no improvement is needed. Allow 45cm (18in) between plants.
Watering of well-established plants in medium to heavy soils should be seldom needed, but plants growing in light, free-draining soils might need watering every two weeks in dry spells.
Deadheading to remove spent flowering spikes helps promote a long season of flowering.
Aftercare is important to ensure a good show is subsequent years. Each spring apply a balanced, general-purpose fertiliser at the rate of 70g per sq m (2oz per sq yd), followed by a 5-8cm (2-3in) mulch of well-rotted organic matter to help promote strong healthy growth. Penstemons flower on new vigorous growth that is not lush.
See the RHS Penstemon Grower Guide for more cultivation advice.