Penstemon; these elegant easy-to-grow border plants send up spires of tubular flowers in a range of gorgeous colours. From sky blue to rich plum, deep purple to powdery pink, they flower across the summer months, and like a warm, sunny spot.

Sow annual Penstemon indoors between February to April. Place seed on the surface of a good free draining, damp, seed compost. Cover with a very fine sprinkling of compost or vermiculite. Place in a propagator or seal container inside a polythene bag until germination. Do not exclude light, as this helps germination. Germination is slow, but don't lose patience, it is always worth retaining your seed tray through the summer if you've had low rates of germination to see if anything happens and if so you can pot-on and overwinter these plants for use the next year.

Transplant seedlings when large enough to handle into pots. Grow on in cooler conditions for 10 to 15 days before planting out after risk of frost, 60cm apart. Water well until plant are established.

You can sow Perennial varieites, such as Mystica in two main windows: February to April for strong first‑year plants, or July to September for flowering the following summer. Spring sowings grow steadily through the season and are ready to plant out after the last frost. Late‑summer sowings germinate well in the warmth, then settle into small, sturdy plants that overwinter happily with a bit of protection.

Sow the seeds on the surface of moist compost — they need light to germinate — and keep them at around 15–20°C. Germination can be a little slow and uneven, so don’t give up too soon. Once seedlings are large enough to handle, pot them on and grow them in bright light with good airflow. They dislike sitting wet, so keep watering light but consistent.

Plant out in full sun or part shade in well‑drained soil. ‘Mystica’ is drought‑tolerant once established and copes well with poor soil, though it appreciates a little compost in the planting hole. Cut back the spent flower stems after blooming to keep the plant tidy, and give the whole clump a light trim in late winter or early spring to encourage fresh growth.

This is a long‑lived, low‑maintenance perennial that brings colour, height and movement to borders. It’s also excellent for cutting — the stems last well in a vase and add a lovely airy quality to arrangements.