For the past two growing seasons, I’ve tried to develop an appreciation for plants with black foliage, but it’s not working. Newly bred black plants like ‘Black Scallop’ ajuga, black-brown ‘Australia’ canna and ‘Black Magic’ elephant ears (Colocasia esculenta ‘Black Magic’) are just unappealing to my clearly unsophisticated garden tastes. But I do see the need for diversity in foliage colour, and that’s how I’ve come to appreciate ‘Husker Red’ and ‘Dark Towers’ penstemons. I think I’m going to like red foliage a lot better than black.
Both penstemons have emerging burgundy foliage, which contrast well with the green and variegated foliage of neighbouring plants. They’re most effective when grown in full sun and planted in a triangle of three to generate best colour impact. ‘Husker Red’ (Penstemon digitalis ‘Husker Red’, Zone 4) is an old favourite, with 24-inch (60-cm) spikes of white tubular flowers atop rigid stems in late spring through early summer. Its burgundy spring foliage softens to bronzy red in midsummer. While recently looking for a few pots of this plant, I came across its cousin, ‘Dark Towers’ (Penstemon ‘Dark Towers’, Zone 4), with darker foliage and pale pink flowers. ‘Dark Towers’ was developed at the University of Nebraska, and is three feet (90 cm) tall with with dark maroon or wine-red foliage that retains its colour all season.
Penstemons are clump-forming perennials, and will perform well in heat, humidity and a short drought. They like average garden soil with good drainage and all the sun they can get. I’ve set them in a bright location that tends to have dry soil, but like every garden plant, they’ll do better with regular watering. I intend to be very good to these red-leaf penstemons, because I’m starting my own trend away from black and on to red. Maybe it will catch on.