Penstemon

Penstemon are generally easy to grow as they require very little care and attention in your garden. The trick is to plant them in the right site to begin with. They are a long flowering, easily cultivated hardy perennial that flowers all summer and is resistant to drought. What more could you ask for? They are also not really bothered by pests and are not eaten by rabbits, slugs or snails. They tolerate lime happily and do not need staking. They don't usually need feeding, in fact overfeeding prevents them forming flower spikes and you just get lots of lovely green leaves.
Plants may be purchased from shows, our nursery or our online shop.

In your garden

They prefer an open sunny border to get the most flower with strong colour. Although they can tolerate some shade they are definitely better in sun. The best site would be full sun all day, the second best is lots of warm afternoon sun and in any other situation I would discount Penstemon.

Good drainage is essential so if you have a heavy soil, then add lots of grit or organic matter when planting. We successfully grew them on Vale of Evesham clay for 10 years, once grit was added. Waterlogged soil in the winter is the Penstemon's nemesis and more are killed by winter wet than cold temperatures so improve your soil on planting if you are on clay. We have had most of our varieties down to -11 degs C with no loss of life!!

Planting

The ideal time to plant Penstemon is in spring or summer. It is better to plant them when they have an established root system as they can be fussy when young. Our main reason for selling plants in larger pots rather than plugs or 3 inch pots is exactly this. If you buy a plant from us it is ready to be put straight into your garden.

Plant them about 18” apart – although this will vary slightly depending upon the ultimate spread of the plant. Once established they do not like to be moved, so choose a permanent site where they will have sun and space to grow. Consider whether the variety you are planting is more upright or more sprawling in habit. Penstemon are quite dull at the bottom half of the plant and punchy with flower at the top so look great in a mixed perennial border.

Pruning

The timing of pruning with Penstemon is crucial to their success. They should be pruned in Spring when the new shoots are 3-4" long. This could be in March, April or May dependent on where you live and the Spring weather. Here in the midlands we generally do ours around Malvern Spring Gardening Show time, i.e. the first week of May.

All of the summer growth should be left on the top of the plant in winter as this protects the crown, any new emerging shoots in Spring and give the roots something to do in the wet winter. You can take the top of the flower spike and seed heads off to tidy up the plants and stop them rocking so much in the winter winds.

Once the new shoots are 3-4” long, it is safe to cut back all the old stems to a new shoot. This can either be to ground level if the new shoots are form there or down the stem to good new growth.

Deadhead

It is a good idea to dead head them throughout the summer as this helps to promote new flowering shoots. Once a flower spike is over, cut it off the plants at the base of the spike where there are 2 strong side shoots. Do not cut back to the ground.

Penstemon

In your garden

Planting

Pruning

Deadhead

More information