Plant breeders have shaken up the old fashioned penstemon, and given it a new lease of life. Graham Clarke takes a look
Penstemons first came onto my radar about 25 years ago.
Previously I had never been very interested, and considered them rather mundane plants. But then I was given a Penstemon ‘Osprey’.
Not realising its potential, I popped it in a gap in the border and more or less forgot about it. That summer, when it was in full flower - white with beautiful pink lobes - it was the talk of the family. I pointed it out to anyone even vaguely interested in gardening! “Oh yes,” I’d say dismissively, “it’s a penstemon. I’ve always grown them you know!” That might not have been true, but I’ve certainly grown them ever since!
These flamboyant, large-flowered plants have been favoured by cottage gardeners for more than a century. They were deemed to be colourful, long-flowering and undemanding. This last point was accepted because, even though penstemons were known to be perennials, they were mainly used as summer bedding, with plants pulled up and discarded in autumn.
Winter hardiness
In recent years, breeding work in penstemons has exploded. This, and their informal habit, has made them popular with contemporary gardeners, and some cultivars are being sold now specifically as container plants.
Most of the penstemons available today are derived from just one Mexican species so, as you might expect, mild, dry winters are preferred. However, in Britain our winters are cold and wet, therefore the penstemon has gained a reputation for being a bit difficult to overwinter. However, do not let this put you off – for there are ways around the problem.
Some gardeners cut back their penstemons by a third to a half in autumn. This reduces the amount of above-ground growth to be killed off. Others reckon that penstemons should not be deadheaded or cut back at all after the end of September - and not pruned down for the new season until the end of March at the earliest.
Meanwhile, some gardeners believe that the cultivars with narrow leaves (including the red ‘Schoe holzeri’, often sold as ‘Firebird’), are hardier than those with broader leaves (such as the mauve and white ‘Alice Hindley’). This may indeed the case, but I haven’t seen conclusive proof of it.
Remember, hardiness varies between varieties, between gardens and between years, so it is nigh impossible to give a definitive ‘yay’ or ‘nay’ as to whether a specific penstemon will survive in a specific garden. Regardless of the thoughts of gardeners around the country, I cut back my plants by about a third, late in the year, and then ‘butcher’ them in the
