Flora of Northern Ireland

Hedgerows and field boundaries

Nineteenth century hedgerows near Carrickfergus, Co AntrimIn the modern Irish farm landscape the land is parcelled out into fields which are bounded by either stone walls or hedges.

Stone walls

Dry stone walls, such as those found in the Mourne Mountains or parts of Co Down, support little or no plant life except bryophytes and lichens. Mortared stone walls can be very rich in plants and there are several species which are characteristic of such walls


Hedgerows

Drawing: hawthorn hedge on earth bank with stones on one side.The majority of hedgerows in Northern Ireland are of comparatively recent origin - probably mid-nineteenth century. Frequently they consist of an earth bank, faced with stones on one side and with hawthorn planted between the stones at the time of construction. The construction of the earth bank often resulted in a corresponding linear depression or ditch which runs parallel to the base of the bank. This ditch is frequently damp or carries a small stream.

This type of field boundary can be rich in plant species. The commonest hedging shrubs used were hawthorn (Crataegus monogyna and sometimes Crataegus x macrocarpa) and blackthorn (Prunus spinosa). But other species of shrub were occasionally used such as Japanese Privet (Ligustrum ovalifolium) in parts of south-east Co Antrim, laburnum (Laburnum x watereri) in south Co Londonderry, wild plum (Prunus domestica) around orchards in Co Armagh, and fuchsia (Fuchsia magellanica) near the coasts. With the passage of time, various other shrub and tree species invade and establish themselves in hedges, or sometimes were planted locally. The most frequently encountered of these include:

Ash Fraxinus excelsior
Beech Fagus sylvatica
Oaks Quercus spp.
Hazel Corylus avellana
Elms Ulmus spp.
Sycamore Acer pseudoplatanus
Elder Sambucus nigra
Apple Malus domestica
Brambles Rubus fruticosus agg.
Honeysuckle Lonicera periclymenum
Roses Rosa canina, R. pimpinellifolia, R. sherardii, Rosa arvensis etc.
Snowberry Symphoricarpos rivularis

In below the trees and shrubs, on the hedge banks, are a variety of herbaceous species, some of which are characteristic of woodland. The most characteristic herbaceous plants of hedgebanks include:

PrimrosePrimula vulgaris
Wood sorrelOxalis acetosella
Wood anemoneAnemone nemorosa
Cuckoo pint Arum maculatum
Herb Robert Geranium robertianum
Early purple orchidOrchis mascula
Robin-run-the-hedge Galium aparine
Greater stitchwortStellaria holostea
BluebellHyacinthoides non-scriptus
Hedge parsleyAnthriscus sylvestris
Scaly male-fernDryopteris affinis
Male-fern Dryopteris filix-mas
Lady-fern Athyrium filix-femina
Hart's-tongue Phyllitis scolopendrium
Soft shield-fern Polystichum setiferum

Hedges of whin (Ulex europaeus) can be seen in many places. These have formed naturally by the whin colonising an unplanted bank, or invading the gaps in a poorly maintained hawthorn hedge.


Dating a hedge

In about 1971 Dr Max Hooper pioneered a method of dating hedges to the nearest 100 years by relating the number of woody species in a hedge to its age. This method, while it appears to work in the southern half of England where ancient hedges are frequent, cannot be used in Northern Ireland because the vast majority of hedges are only about 250 - 150 years old.

Hedges can sometimes be dated by reference to old maps, estate records etc.

Further reading

Robinson, Philip (1977), The spread of hedged enclosure in Ulster. Ulster Folklife vol. 23 pp.57-69