Juniperus communis L.
Family: Cupressaceae

Juniper is one of the few conifers native to Ireland and is a prickly shrub producing a blue-black fleshy berry. It is widespread across the temperate regions of the northern hemisphere.

In brief

• Rare and local in Northern Ireland
• Found in the Mourne Mountains, around the basalt cliffs in north-east County Antrim and the north of County Londonderry and in the Carboniferous limestone areas of County Fermanagh
• Mainly restricted to areas of cliff inaccessible to grazing or limestone pavement
• The plant is an evergreen perennial which can be seen at any time of year
• Listed as a UK Priority Species
• It appears to have been lost from many sites within the past century
• Causes of decline are unclear but may include grazing, burning, scrub clearance and vegetational succession.

Species description
A shrub with short needle-like leaves and a fleshy blue-black berry. Growing either as a low plant pressed to the rocky ground on which they normally occur, or as a more erect shrub.

Life cycle
Juniper is a conifer, with separate male and female plants. Male plants produce small pollen-producing cones, while females produce small seed-bearing cones; pollination is by wind. Unlike most conifers, the female or seed cones of junipers become fleshy and the scales of the cones coalesce into a berry-like structure, containing between one and three seeds, which is eaten by birds. From pollination it takes two or three years for the berry to develop to maturity. The seeds pass unharmed through the bird’s gut and can germinate to form new plants.

Similar species
Juniper cannot be confused with any other shrub growing in the wild. However, there are many similar foreign species in cultivation.

How to see this species
A specimen plant of Mourne Mountains origin is in cultivation at the walled garden, National Arboretum Castlewellan Forest Park.

In the wild, it is to be found at a number of sites in the Mourne Mountains, around the basalt cliffs in north-east County Antrim and the north of County Londonderry and on exposed Carboniferous limestone in western County Fermanagh (Marlbank Loop area). It can be seen at any time of year. Relevant access permissions should always be sought prior to visiting any sites.

Current status
Found in the Mourne Mountains, around the basalt cliffs in north-east Co. Antrim and the north of Co. Londonderry and in the Carboniferous limestone areas of Co. Fermanagh. This is now a scarce and local species which seems to be in decline. It has not been seen at over 50% of its recorded sites since before 1986.

Why is this species a priority in Northern Ireland?

• It is listed as a UK Priority Species
• It has declined and is scarce.

Threats/Causes of decline
Causes of decline are unclear but may include burning, scrub clearance and vegetational succession. The major threat probably remains overgrazing.

However, Phytophthora austrocedrae has recently been confirmed in juniper plants in Cumbria in North-West England; at Glen Artney in Perthshire, Scotland; and in a nursery and a private garden in Devon in South-West England. (Green et al., 2012).

Above-ground symptoms on infected pants include dieback of the foliage, stem and collar lesions. The root/collar infection is described as ‘tongue-like’; this can be observed by removal of the outer bark, whereupon the phloem is necrotic, often cinnamon brown, with a distinct margin between diseased and healthy tissue.

When roots and collars/stem bases are affected, foliage of infected trees initially appears a slightly lighter colour than that of healthy trees. Later the foliage withers, turns bronze, and finally, light brown, concurrent with drying and darkening of the inner bark.

Anyone who suspects they have seen symptoms of P. austrocedrae infection of Juniper should report it to:

Biodiversity Unit, NIEA

Email: biodiversityunit@doeni.gov.uk

Reference:    Green S, Hendry SJ, MacAskill GA, Laue BE, Steele H, 2012. Dieback and mortality of Juniperus communis in Britain associated with Phytophthora austrocedrae. New Disease Reports 26, 2.

Conservation of this species

Current action
There is a UK Species Action Plan which was published in 1999.

• Some populations lie within designated areas, for example, the North Antrim Coast, Binevenagh, Eastern Mournes, and the limestone pavement areas of the West Fermanagh Scarplands Special Areas of Conservation. Also some populations lie within areas designated as ASSIs
• Implementation of the Northern Ireland Habitat Action Plans for Upland Heathland, Calcareous Grassland and Limestone Pavement.

Proposed objectives/actions

• Maintain the current range of juniper
• Maintain the overall population size of juniper
• Achieve natural regeneration of juniper populations at sites under direct conservation management
• Maintain, or re-establish, populations at sites not under direct conservation management
• Maintain existing populations outside ASSIs wherever possible by encouraging landowners to manage their land in ways that encourage juniper, and by offering advice and practical assistance for such management.

What you can do
Records of sightings of this species are important. Send any records to either BSBI, c/o Department of Botany, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU or to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU. Tel: 028 9039 5256, cedar.info [at] nmni.com.

If you are a landowner with juniper growing on your land, please be aware of its conservation value and requirements.

Further information

Links
UK Species Action Plan for juniper

Northern Ireland Habitat Action Plans

Flora of Northern Ireland

Literature
Bean, W.J. (1973). Trees and Shrubs Hardy in the British Isles. Vol. II: D—M. John Murray.

Phillips, R. (1978). Trees in Britain, Europe and North America. Pan/Ward Lock London.

Van Gelderen, D.M. and van Hoey Smith, J.R.P. (1996). Conifers— The Illustrated Handbook. Vol. 1: A—K.

Text written by:
Paul Hackney

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