Bentley Priory

Also within

Greater London County

Condition (Natural England)

Habitats

Ancient woodland, Coppiced woodland, Mixed scrub, Montane scrub

Description

Description Bentley Priory comprises an intricate mosaic of unimproved neutral grassland, ancient and long established woodland, scrub, wetland and open water. This combination of habitats is uncommon in Greater London. Several plant species which are rare or scarcein Greater London are present and the site supports a characteristic breeding bird community. The site lies on the south facing slopes of a ridge capped by Pebble Gravels. The lowerparts lie on London Clay; further north the transitional Claygate beds of sand and loam flank the central valley, while pebble gravels are present on the northern extremity. The soils are freely draining and acidic in the north and vary through sands and loams to the heavy neutral soils in the majority of the site. Streams and springs arise at the junction of the impervious London clay and the overlying Claygate beds, including the Edgeware Brook, which has been dammed to form a lake. Boot Pond in the extreme south east is also spring fed. Bentley Priory supports some of the largest neutral meadows in Greater London, with transitions to more acidic conditions on the northern slopes and to marshy grassland at the lowest levels and around streams and flushes. These grasslands have been traditionally maintained by grazing. In general, common bent grass Agrostis capillaris is ubiquitous with red fescue Festuca rubra, Yorkshire fog Holcus lanatus and crested dog’s tail Cynosurus cristatus all common. The more acidic, freely draining pastures in the north are characterised by the occurrence of sheep’s fescue Festuca ovina and occasional wavy hair grass Deschampsia flexuosa. On the clay creeping bent Agrostis stolonifera is frequent, with tufted hair grass Deschampsia cespitosa, rye grass Lolium perenne and meadow fescue Schedonorus pratensis. Herbs associated with the grasslands include common knapweed Centaurea nigra, selfheal Prunella vulgaris, common and greater bird’s foot trefoils Lotus corniculatus and L. uliginosus and sneezewort Achilles ptarmica in the damp areas around Boot Pond. Also found here is great burnet Sanguisorba officinalis, a species scarce in Greater London. On the higher slopes, where ant hills are locally frequent, species such as harebell Campanula rotundifolia and heath bedstraw Galium saxatile are present while on the Claygate beds pignut Conopodium majus occurs with adder’s tongue Ophioglossum vulgatum which is scarce in Greater London and pepper saxifrage Silaum silaus, both of which are largely associated with old meadows. Scrub occurs in stands throughout the grassland, mainly dominated by mature hawthorn Crataegus monogyna, with gorse Ulex europaeus and broom Cytisus scoparius in the north and occasional guelder rose Viburnum opulus on the clay site. The site is unusual in London for the presence of five species of rose, including glaucous dog rose Rosa dumalis at its only London locality and short styled field rose R. stylosa and small flowered sweet briar R. micrantha which are both scarce in Greater London. Heriot’s Wood is the largest ancient woodland in the Borough of Harrow and is dominated by hornbeam Carpinus betulus and pedunculate oak Quercus robur. Many of the hornbeam trees are mature multi stemmed standards derived from old coppice stools. Midland hawthorn Crataegus laevigata, a species strongly associated with old woodland, occurs in the shrub layer with silver birch Betula pendula and common hawthorn Crataegus monogyna. The deep shade cast by hornbeam combined with cattle grazing limits the ground flora which is dominated by bramble Rubus fruticosus with wavy bitter cress Cardamine flexuosa in damp areas. This stand grades into lowland hazel pedunculate oak woodland near Bentley Priory Lake outflow, with alder Alnus glutinosa in the wet flushes. A diverse ground flora includes remote sedge Carex remota, a species strongly associated with ancient woodland, creeping jenny Lysimachia nummularia and great horsetail Equisetum telmateia. Other woodland on the site contains a more varied canopy including wild cherry Prunus avium and rarely wild service tree Sorbus torminalis, both of which are largely associated with ancient woodland. The ground flora, though dominated by bramble, includes many species typical of ancient woodland such as ramsons Allium ursinum, pendulous sedge Carex pendula, wood sedge Carex sylvatica, wood millet Milium effusum, greater burnet saxifrage Pimpinella major, goldilocks buttercup Ranunculus auricomus, sanicle Sanicula europaea and soft shield fern Polystichum setiferum which is scarce in Greater London. The streams flowing south and east through the site and the flushes on the slopes support a flora including common spike rush Eleocharis palustris, together with water horsetail Equisetum fluviatile which is scarce in London. Both Boot Pond and Bentley Priory have a diverse marginal and emergent vegetation including imperforate St John’s wort Hypericum maculatum, rare in Greater London and cyperus sedge Carex pseudocyperus and greater tussock sedge Carex paniculata, both scarce in Greater London. Bentley Priory supports a characteristic breeding bird community, with many of the species associated with the mature woodland. These include all three British species of woodpecker, green Picus viridis, greater spotted Dendrocopos major and lesser spotted Dendrocopos minor, nuthatch Sitta europaea, tawny owl Strix aluco, treecreeper Certhia familiaris and tree sparrow Passer montanus. Also breeding at this site is hawfinch Coccothraustes coccothraustes, which is often associated with mature hornbeam woodlands and has a localised distribution both in London and nationally.

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