Penn's Rocks

Also within

East Sussex County High Weald Scenic Area

Condition (Natural England)

Habitats

Bracken scrub, Coppiced woodland

Geology & landscape

Rock Type: Sandstone

Description

Area, 10.1 ha. 25 ac. Description At Penn's Rocks outcrops of the Ardingly Sandstone Formation of the Hastings Beds are exposed in a steep sided wooded valley. The resulting 'sandrock' is a nationally rare habitat which supports a rich community of ferns and bryophytes mosses and liverworts including many 'Atlantic' species which are uncommon in south east England. The site comprises four blocks of woodland each with sandstone outcrops. In the southern areas pedunculate oak Quercus robur and beech Fagus sylvatica are dominant, with varying amounts of silver birch Betula pendula, yew Taxus baccata and holly Ilex aquifolium over a ground flora of bramble Rubus fruticosus and bracken Pteridium aquilinum. In the north Scot's pine Pinus sylvestris and silver birch dominate in a heathy woodland over a ground layer including heather Calluna vulgaris, bilberry Vaccinium myrtillus and bracken. The site also contains small areas of coppiced sweet chestnut Castanea sativa and improved grassland. The warm, moist microclimate provided by this woodland cover has allowed species to remain which are now restricted to northern and western Britain and a few localities in the Weald. This sandrock community contains many uncommon bryophytes including Orthodontium gracile, Bazzania trilobata, Saccogyna viticulosa and Harpanthus scutatus.

Species mentioned

Insects to look out for

These moths, butterflies and beetles are known to feed on plants recorded at this site, and carry a notable UK conservation status — but a host-plant being present doesn't mean the insect has actually been recorded here. Treat this as "worth watching for," not a confirmed sighting.

Host-plant data: Cook et al. (2025), Traits data for the butterflies and macro-moths of Great Britain and Ireland, 2024, UK Centre for Ecology & Hydrology / Butterfly Conservation; and Padovani et al. (2020), Database of Insects and their Food Plants (DBIF), UK Centre for Ecology & Hydrology (both Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.

Plant communities