Hypericum calycinum

Scientific profile

Hypericum calycinum is a low, woody, evergreen shrub (growth form ‘Strauch’) with broad leaves (leaf type ‘Breitblättrig’). It typically reaches about 0.3 m in height. The leaves persist year-round (leaf phenology ‘Immergrün’) and have an average area of 1641 mm². Flowers are borne from July to September. The plant forms arbuscular mycorrhizal (AM) associations. Its environmental requirements, as indicated by Ellenberg-type values, are partial shade (light value 5), moist conditions (moisture value 7), a neutral to weakly acid soil reaction (value 5), moderate nutrient supply (value 5) and a preference for warm sites (temperature value 8). Seeds are small, with a mean diaspore mass of about 0.45 mg. The reported distribution includes south-western and south-eastern Europe and temperate Asia. In Great Britain, it is recorded as an introduced species that has become established (Plant Atlas 2020).