Penstemons are versatile, long flowering and generally pest & disease free. What is more they are fabulous border plants. Penstemons are perennial, long-flowering and easy to grow. They thrive in fertile, moist, free-draining soil. They’re fairly easy to look after, only requiring occasional watering in very dry weather or if planted in very light, free draining soil.
Penstemons will flower from late summer until late autumn, when they die right down to the base. Unless there’s a very severe winter, they grow back the following year and flower again. Unlike more hardy perennials in your border, it’s best to keep their stems and foliage in tact throughout the winter to give them that little extra bit of protection from frost or snow. When the weather begins to warm in spring, you can cut the stems right down to the base and allow fresh new growth to take its place.
They prefer light shade or full sun and will attract Bees, Butterflies and other beneficial insects. Penstemons that are grown from cuttings give a larger, more vigorous plant with stronger, better developed roots. They are quick to establish and can be planted into their final growing positions providing all risk of frost has passed.
Growing From Seed
Penstemons are easily propagated from seed sown in early spring in heated conditions and planted out in early summer. However they are unlikely to come true to the parent plant so the best way to propagate them is to take softwood cuttings.
- When planting outside wait until risk of frost is passed to give them the best chance. Late May is usually fairly safe, but different locations may vary.
- Thoroughly dig and water the soil first.
- Dig an individual hole for each plug, deep and wide enough for the entire root ball.
- Position the plant into the hole and backfill with soil.
- Water-in after planting.
Tips On Growing Penstemon Plants
- Enrich the soil with organic matter and general purpose fertiliser when planting out – this will aid good establishment. In subsequent years, add fertiliser and a mulch of well-rotted organic matter each spring.
- Allow approx 45cm (18in) between plants and protect from slugs when plants are still small.
- Deadhead spent flowering spikes to prolong the flowering season.
- Trim back in the spring once the worst of the winter weather has passed (usually in late April or early May) – the old stems provide frost protection for the new shoots.
- Keep well watered when first planted to make it a good environment for your Penstemon to establish a strong network of roots. In following years, it will only be necessary to water your Penstemon occasionally.