The penstemon - robust, long-flowering, bee-friendly - has fallen unaccountably out of favour with fashionable gardeners, writes Jane Powers
The penstemons are roaring their heads off now. Their spikes of open-mouthed flowers are all tonsils and tongues: a massed, floral primal scream. (Or perhaps they're just yawning at the far-fetched metaphor.) These foxglove-relatives start flowering in June, and, if they're not hit by frost, they'll go on blooming (with the occasional little hiatus) until December. I'm talking about the hybrid varieties here - most of which have been bred in Europe over the past century or so. The wild species kinds, all of which are natives of north and central America (except for a single Asian species), have a shorter flowering period.
Borne on small spires, the penstemon's two-lipped, tubular bells identify it as a member of the large Scrophulariaceae family, which includes - besides foxglove - snapdragon, veronica and toadflax, as well as (less obviously) verbascum and hebe.
The common name, beard-tongue, pays tribute to the mouth-like flowers, and refers specifically to the flattened fifth stamen (properly called a staminode) which is covered in fine hairs. Next time you are passing a penstemon, look down its throat to admire its hairy tongue and often strongly-marked gullet. It is one of those flowers whose innards are just as handsome as its "outards".
It is also a flower that has, unaccountably, fallen somewhat out of favour with fashionable gardeners. I'm not sure why. Perhaps it is because the growth habit of some varieties is too shrubby for today's naturalistic and airy borders, where tall, slim plants are the norm. Or perhaps it's because they are not reliably winter-hardy in Britain or parts of northern Europe - from where many plant fashions emanate.
But let's not dwell on why the poor old beard-tongues are not so voguish these days. Instead, let's look at why they are remarkably congenial plants, and why every Irish garden should make room for them. Our climate, it is worth remembering, is milder than that of our nearest neighbours, allowing us to grow a much wider range of plants, except in the chillier parts of the country (not that we're boasting, of course).
The hybrid penstemons' most valuable asset is their long flowering period, providing coloured bells for months on end, if you give them the right treatment. After the first spikes finish blooming, cut the stalks back to a leaf joint just below where the lowest flowers have faded. This will encourage new flower shoots.
Penstemons are evergreen, so they don't disappear underground in winter. They don't need staking, and are exceptionally wind-proof: the stems bend, rather than break, and the flowers suffer only a little in the strongest gale. They are also almost impervious to drought, holding their heads up proudly in the driest of soils. Indeed, they don't like a damp clay (especially in winter), so heavier soils should be treated to some extra grit or sand for drainage.
Like many of their fellow Scrophulariaceae clansmen, they are robust individuals, and rarely succumb to disease. And, best of all, slugs and snails completely shun them, while aphids are utterly uninterested in them. Bees, on the other hand, can't keep away, and are busy all day, bumbling from tube to tube in search of nectar. To guide the buzzing honey-makers, Nature has painted a pretty tracery of parallel lines along the inside of the corolla, leading the way to the nectaries.
What more could a gardener want in a flower? Especially as there are over 200 large-flowered hybrids available, all in sugary or fruity colours: white, pink, cherry, plum, mauve, lilac and purple; and many of them with beautifully marked and contrasting throats. True blue penstemons are rare, but there are some, such as 'Stapleford Gem' and the tall P. heterophyllus, that shimmy iridescently between sky-blue, violet and pink.
You won't see a better display of beard-tongues in Ireland than in Burton Hall in Sandyford, where the 55-metre-long double border houses about 120 different varieties. It is given over entirely to penstemons, except for a low haze of 'Sawyers' lavender that makes a purple-tinged bolster of cloud along the front of the border.
Head gardener Berna Purcell keeps track of her many varieties by planting them in alphabetical order. It's a unique way of planning a border, but because the colours all belong to the same warm and sweet part of the spectrum it is surprisingly effective. There are far too many beauties for her to nominate favourites, but she gamely tries. Among them are the two Irish-raised penstemons, 'Beech Park' and 'Evelyn'. The first has large pink flowers with white throats, while the second is most elegant, with narrow leaves and dainty, rose-pink bells.
Berna entirely replants the border every two years, an operation that keeps it looking its best each summer. And while some gardeners recommend trimming penstemons hard back each spring, Berna thinks that this delays their flowering unnecessarily. Instead, she takes a third off the top in December, "to stop wind-rock" and then cuts back another third in spring. Such a regime sees them well in bloom by mid-June.
Although penstemons may not be at the haute couture end of garden fashion, breeders are still creating new varieties. Susan Carrick (of the Potting Shed nursery in Camolin, Co Wexford, tel: 054-83629) raves about the showy Pershore hybrids, such as the pink and crimson 'Elmley' and the mauve-pink and maroon 'Bredon'. "Very, very long-flowering, richly-coloured and well-marked," she says. "Fabulous plants!" jpowers@irish-times.ie