Slender St John's-wort

Hypericum pulchrum is a slender perennial herb in the family Hypericaceae, typically growing 20–50 cm tall with wiry, reddish stems and small, paired oval leaves dotted with translucent glands. From summer into early autumn it produces bright yellow, five-petaled flowers, often tinged red on the buds and petal margins, which attract a range of pollinating insects. As with other St John's-worts, its foliage contains hypericin and related compounds that deter herbivory.

The species contributes to the floral diversity of open, low-nutrient grasslands and heathland margins, offering nectar and pollen resources to solitary bees and other invertebrates.

The plant occurs widely across western and central Europe, including the United Kingdom, Ireland, France, Germany, Belgium, the Netherlands, Scandinavia, and parts of the Iberian Peninsula and Mediterranean, with additional records in North Africa, the Korean Peninsula, and introduced or naturalised populations in Australia, New Zealand, and the United States. It favours dry to moderately moist acidic soils in grasslands, heaths, woodland edges, and rocky or sandy open ground.

Its decline is driven by agricultural intensification and conversion of semi-natural grassland to cropland or improved pasture, fragmentation from urban expansion, nutrient enrichment from fertiliser runoff and atmospheric deposition, and the loss of traditional low-intensity grazing that historically maintained open habitat structure. Without grazing or cutting, sites are increasingly lost to scrub and woodland succession.

Conservation responses include habitat protection within designated grassland and heathland reserves, agri-environment schemes encouraging low-intensity grazing, and monitoring by national botanical recording schemes. No population figures are available, and the trend is currently classified as unknown. Continued habitat management will likely determine whether local populations stabilise or continue to contract.

Slender St John's-wort inhabits acidic heathlands, moorlands, and nutrient-poor grasslands, typically on sandy or peaty soils. It thrives in open, sunny locations with low soil fertility, often associated with traditional extensive grazing systems and areas maintained by periodic disturbance.