Adiantum x mairisii AGM

Maries's Maidenhair Pteridaceae

Adiantum × mairisii is a particularly elegant hardy maidenhair fern, with a rather fascinating Victorian history. This sterile hybrid was raised at Mairis & Co. Nursery in England before 1885, apparently involving Adiantum capillus-veneris and an unidentified second species, with A. raddianum and A. aethiopicum suggested as possible parents. It was subsequently named by the eminent fern specialist Thomas Moore, curator of Chelsea Physic Garden, who described it in the nineteenth century. The hybrid is notable for being considerably hardier than its presumed parents, while retaining the exquisite, finely divided foliage that makes maidenhair ferns so irresistible. 

The arching fronds are carried on slender, almost black wiry stipes, each bearing delicate bright-green fan-shaped leaflets. It slowly spreads by creeping rhizomes to form a graceful colony, rather than a congested clump, and is generally deciduous in colder winters. In cultivation, give it humus-rich, moisture-retentive but well-drained soil in partial to full shade, with protection from drying winds. It appreciates regular moisture through summer, but dislikes stagnant winter wet. A superb fern for the front of a woodland border, shaded rockery or as an underplanting beneath shrubs. The old name Adiantum capillus-veneris ‘Mairisii’ is still encountered in horticulture, but the hybrid name A. × mairisii is the more appropriate treatment. 

Hardiness: H5, approximately −15 to −10°C
Height: 35–45cm
Spread: 60–90cm