Penster power
PENSTEMONS ARE PERFECT FOR ADDING COLOUR TO YOUR HERBACEOUS BORDER
ALTHOUGH we are still in winter, it’s time to think about spring planting and what lovely herbaceous plants to use in the garden this year.
A good perennial for me is one that flowers for a very long period, has attractive foliage as well and isn’t too fussy about either its soil conditions or maintenance requirements.
One plant that ticks the boxes and that I often include in my herbaceous planting schemes is penstemon. It’s quite similar in appearance to a foxglove as it has spires of bell shaped flowers, and just as with foxgloves, bees love to burrow inside for the nectar.
So when foxgloves finish flowering in early summer, you can keep the show going with penstemons.
The majority of penstemons are native to America and fans of this genus are called Penstemaniacs, who gather each year to talk about and observe penstemons growing in their native habitats. On this side of the pond, European plant breeders have created many hybrids and cultivars and the range of flower colour is wide. From fiery reds to electric blues, raspberry ripple pinks and lavender to rich purples, there is a penstemon for every colour scheme.
‘Heavenly Blue’ has gorgeous summer sky blue flowers with a hint of pink inside. ‘Raven’ is a velvety deep plum colour and ‘Garnet’ is a popular bright crimson variety.
Softer colours such as pink and white combos are available such as the very pretty ‘Apple Blossom’. ‘Sour Grapes’ is a lovely purple or you might just prefer a simple white variety.
There are some alpine varieties which are suitable for rockeries but in general they are best suited to floral borders as well as garden pots, forming bushy shrub shapes.
Penstemons are semi-evergreen but if you have very cold winters it’s worth protecting the roots with a good mulch.
I leave them over winter and cut back in around April.
They can look a bit messy by the end of summer when they start to collapse but I think it’s best to leave them as is. If you prune hard at this stage you will get tender growth that won’t survive a harsh winter. It’s a good idea to take cuttings in summer to propagate as insurance. They propagate well from cuttings – mid to late summer is the best time to do this. Pick a healthy non-flowering shoot and cut below a leaf pair.
Remove leaves from the cutting, leaving just one pair, and get it into your cuttings compost as soon as you can.
Penstemons can be short lived perennials so this is a good way to keep your stock going. You can also grow them from seed but this needs to be done in early winter as they need a cold period to germinate.
Plant in full or partial sunshine in moist but well-drained soil.
They are quite drought tolerant but don’t like the crown or their roots to sit in soggy soil.
Deadheading will help prolong the flowering period and you can also remove finished flower stalks from the base and you may get a second – albeit smaller – spike of fresh flowers.