They look a bit like small foxgloves, but penstemons have a lot more going for them, particularly colour, which is why I am a bit sad to have to say I am currently mourning the passing of a particularly vibrant specimen.
P ‘Burgundy’ has (had), not surprisingly, intense burgundy blooms and like many of its ilk, it bloomed magnificently for three successive years and then – simply disappeared.
Which is probably the biggest drawback with this wonderful family of normally frost-hardy evergreen or semi-evergreen perennials. They can thrive one year and simply die away the next. Which is why it pays to propagate them. I didn’t, so some of my Christmas money will be spent on a suitable replacement.
Penstemons come in a wonderful array of colours – from pure white through pinks, reds and blues to aubergine.
They are vigorous and their abundance of bell-shaped flowers make for an eye-catching display in July to August. And bees adore them for their plentiful supply of nectar.
They are at their best in herbaceous borders but there’s nothing to stop anyone from growing them where the sun shines and the soil is fertile and well-drained. Even heavy clay can be persuaded to house them – incorporate plenty of well-rotted material and add a few handfuls of coarse grit to encourage decent drainage.
The best way to make sure penstemons keep flowering is to dead-head regularly, and it’s equally important to prune them annually.
In early May, when the worst of winter has, hopefully, gone, trim them back. When new shoots appear at the base, remove the old flower spikes and take a few cuttings. In autumn, cut back established plants by about a third, leaving some foliage to provide protection.
To give plants the best start to a new growing season, apply a balanced, general-purpose fertiliser in spring and then add a hefty mulch because penstemons are greedy feeders.
There are numerous named varieties on offer – if your preference is for red, then take a look at ‘Chester Scarlet’; ‘Alice Hindley’ produces lilac-blue blooms;. And if you want something a little more delicate, then ‘Apple Blossom’ has lovely white-throated pink flowers.
The majority of plants grow to 18ins in height, although some will top 24ins, and ‘Burgundy’ and a few others can better even that.