Polystichum aculeatum, Hard Shield Fern is a handsome evergreen fern native to Europe, including the UK and Eire where it grows on upland rocky outcrops on moist rock surfaces and in crevices but it can also be found in damp gorges and the slopes of wooded valleys. In the UK, it is relatively common and found most often in Wales, Northern Ireland, Scotland and the Borders. It often grows in association with limestone outcrops but will also grow in more acidic substrates.

Polystichum aculeatum has noticeably glossy foliage on its upper surface with an erect arching habit. The fronds become stiff and leathery as they mature.

A remarkably tough fern, Polystichum aculeatum is a great choice for a reliably hardy evergreen fern in a moist exposed aspect but it will also benefit from shade.