Country diary: a coral form with a fondness for dry stone walls

Above a stone retaining wall at the front of my flower border, I grow mounds of a succulent herb known as roseroot. Rising out of a sea of forget-me-nots, their rounded shapes resemble strange coral forms. Their colouring of glaucous leaves and lemon yellow flowers adds to that underwater feeling; I almost expect small fish to be sheltering in their rhythmic branching.

They are termed herbs because the dried rose-scented roots were used in perfumery. Succulents because their water-retentive leaves enable them to live in high alpine conditions among dry rocks.

Native to Britain, roseroot, Rhodiola rosea, grows mostly in the north and west, tucked on to the ledges of sea cliffs, or in mountain areas above 300m. The nearest to where I live is probably on Cross Fell, the highest of the North Pennine hills.

My clumps of roseroot date back to one original that I have propagated over the years. Being dioecious, roseroot bears male and female flowers on different plants; mine are all male so they do not produce seed. But break a piece off and push it into the ground and it will root.

I run my hands up the leaves and, on this day of intense heat, they feel cool to the touch. To do well, roseroot must be grown in full sun. It is drought tolerant but also needs some moisture at the roots, conditions that emulate the rock crevices where it grows wild. The well-drained sunny position above my stone wall is ideal, and suitably for my frost hollow of a garden, this is a very hardy plant that grows as far north as the Arctic.

Each tiny yellow flower has four petals and a starburst of stamens. Insects have been drawn to them since flowering began over a month ago and I’ve counted bumblebees, solitary bees, hoverflies, flies and beetles. It is also a favourite of vine weevil, the fat white grubs feasting on its thick roots in winter before emerging as adults in late spring. When that happens, I slice the damage from the fleshy branches, poke them into the soil where they regrow – and celebrate roseroot’s endurant nature.

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