Ulex europaeus L., Gorse
Account Summary
Native, common, widespread and locally abundant. Oceanic temperate, but very widely naturalised in both hemispheres.
1881; Stewart, S.A.; Co Fermanagh.
Throughout the year.
Growth form and preferred habitats
A much branched, large evergreen, profusely yellow-flowered, conspicuously armed shrub, usually around 2 m tall, but capable of reaching 4 m in height if left to grow once established. All leaves beyond the seedling stage are reduced to prickly, green, acicular, spine-like phyllodes that easily detach and form a persistent spiny litter beneath the shrub. The majority of branches are reduced to form very sharp, rigid, green, deeply grooved spines, 15-30 mm in length, that thickly cover the woody main stems. Larger primary spines branch to form secondary and tertiary spines and they may also bear flowers a considerable distance from their bases. Each bush produces a taproot that usually manages to penetrate at least 30 cm in deeper soils, but most roots are superficial in the top 10 cm of soil (Grubb et al. 1969). The roots have both VA (vesicular-arbuscular) mycorrhiza and nitrogen-fixing nodules that are unusual in being perennial (see below).
The established strategy of U. europaeus is as a stress-tolerant competitor (Grime et al. 1988, 2007). It is particularly abundant and rapidly develops dense thickets in neglected ground which has previously been disturbed, such as on the banks of ditches, streams, rivers and lakes, in hedgerows beside tracks or roads, on woodland margins, in woodland clearings and around human settlements in general. It is frequent on rocky maritime cliff-tops and often forms dominant dense thickets on grey sand dunes (Grime et al. 1988, 2007).
U. europaeus thrives in dry or well-drained, highly disturbed areas and it can invade and grow well in shallow, stony conditions, or in peaty nutrient-poor heathland or bog margin soils, although for optimum development it really requires moderately fertile soils around 20-50 cm deep (Clements et al. 2001). Gorse is more tolerant of soil acidity than most other legumes (Hill 1949) and it produces optimal growth at a soil pH between 4.5 and 5.0 (Meeklah 1979). Gorse does not grow all that well in calcareous soils and, therefore, is much less frequently met in limestone districts, although it is certainly not excluded from them. It can even grow surprisingly well on thin, shallow rendzina soils over chalk and limestone (Proctor 1965). U. europaeus is absent from wetlands, managed meadows and pastures, or cultivated ground.
The distribution and abundance of Gorse is strongly correlated with human disturbance, including all forms of agriculture, forestry and transport, together with the plethora of uses to which the plant has been pressed by man in past times (Lucas 1960; Mabey 1996).
On heathland, there is evidence that U. europaeus is much more exacting in its requirements for certain plant nutrients and mineralizeable salts and it demands a lower carbon:nitrogen ratio than other heathland species, eg Calluna vulgaris (Ling) and Erica species (Tubbs & Jones 1964). Disturbance of the ground in heathland may encourage Gorse growth through the inversion of the soil horizons, releasing plant nutrients from the layered podsol conditions which commonly form in acidic, heavily leached soils. In other soils occupied by Gorse, additional nutrients are made available when soil is heavily trampled and manured by grazing stock.
Gorse and Bracken (Pteridium aquilinum) have long been used as indicators of above-average quality in heathland soils. For example in the New Forest, Hampshire, in the past soils were chosen for cropping on the basis of the old saying, "Under Bracken lies gold, under Gorse lies silver, and under Heather lies lead." (Tubbs & Jones 1964). Another Irish version from Co Kerry has it as, "Gold under furze, silver under rushes and famine under heath." (Lucas 1960, p. 186).
The very presence of gorse acidifies soil through the addition of its litter and the removal of calcium. The high density of living evergreen shoots in Gorse thickets also reduces through fall of incoming precipitation. In one study in New Zealand, precipitation penetration was reduced by 35-50%, with consequent reductions in nutrient run-off and soil moisture levels (Egunjobi 1971).
U. europaeus is generally associated with relatively sparse grassland or scrub communities which allow it to compete for light (Grubb et al. 1969). It is sometimes associated with similar and related shrubs, such as Cytisus scoparius (Broom), but only a few woodland species can grow under the dense canopy of gorse, eg Hedera helix (Ivy) and Rubus fruticosus (Bramble).
Perennation of stems and root nodules
The evergreen stem and spines of gorse photosynthesise all year round and thus actively perennate the plant in conjunction with continuous nitrogen fixation, although as one would expect, growth and nodule activity of the plant is much reduced in winter (Radcliffe 1986; Clements et al. 2001). Unlike many other legumes, Gorse and Cytisus scoparius in N Ireland have been shown to possess truly perennial root nodules, which are branched and can weigh up to one gram. Nodule perennation may only occur during a succession of mild winters and possibly only in soil conditions where decay of the older parts of the nodule becomes arrested (Pate 1961). In one study, Egunjobi (1971) estimated that in a stand of seven year old Gorse, 65% of the nitrogen taken up and fixed by the species was returned annually to the soil.
Flowering reproduction
Under favourable growing conditions, young plants of this spiny polycarpic perennial shrub grow extremely rapidly and they are capable of flowering just two or three years after their germination (Rees & Hill 2001).
U. europaeus flowers in super-abundance, the blossom crowded in spire-like clusters at the tips of the branches. The large, showy, pea flowers vary in degree of yellowness from a soft buttercup to a strong orange, all of them heavily scented of coconut oil. The Gorse floral display continues all year round in B & I, but is at its most impressive from March to early June. There is a legend, loved and often repeated by the Victorians (but very possibly apocryphal), that when the famous Swedish botanist Carl Linnaeus visited England in August 1736 and saw gorse flowering for the first time on some heathland, he fell down on his knees and thanked God for the beautiful display (Blunt 1971, p. 90).
Honey-bees and bumble-bees visit some of the flowers, but there are far too many compared with the number of insect pollinators (Knight 1996). The flowers lack nectar, but bees, if they are sufficiently heavy and vigorous, can trigger the explosive release of copious pollen which then coats the body hairs on the visitor, who then transfers it to the special 'pollen basket' hairs on its hind legs. Once it has been triggered in this way, the flower hangs limply and thus it is most unlikely to be revisited (Proctor & Yeo 1973).
Although gorse flowers are self-compatible, out-crossing is said to result in higher fertility, which would be the expected genetic outcome (Clements et al. 2001). The few quantitative studies that have been made suggest that a large percentage of the flowers fail to set fruit (possibly up to 80% reproductive failure) (Clements et al. 2001). In a coastal district in Wales, however, Knight (1996) estimated that billions of Gorse flowers were unvisited (ie they were unsprung) and this certainly is the case also in Ireland. Knight found that the level of fertility appeared unaffected by being unvisited by bees, since the unsprung flowers all self-pollinated.
The number of seed set was equally low in both instances (insect pollinated and selfed), with approximately twelve ovules per ovary setting a mean of just 2.2 seeds (Knight 1996). Low fertility in Gorse has been shown to be related to the production of poor pollen (ie meiotic abnormalities occurring during microsporogenesis) (Misset 1992). The annual seed production has been estimated in New Zealand as 500-600 per m2 (Ivens 1978).
Seed dispersal
Most Gorse seeds fall beneath the parent plant, but some may be ejected explosively when the pods audibly 'pop' and seed can travel in this manner up to 5 m from the parent plant. Longer distance dispersal involves water, ants (and perhaps birds), and also vehicles. The tough seed coat is water repellent and can resist abrasion in stream gravel. Each seed bears a white nutritive outgrowth from the seedcoat (an elaisome), which attracts ants and perhaps also birds like Quail, where they occur (Chater 1931). Since the plant distribution closely follows agriculture workings, it is presumed that seeds frequently hitch lifts on machinery (and boots) in mud.
Seed and plant longevity
The seed has considerable longevity, persisting in large quantity (up to 20,000 per m2. in the top 6 cm of soil), for as long as 30 years (Clements et al. 2001). It is the ability to produce a large seed bank which helps U. europaeus to persist in many areas since the actual lifespan of individual plants is relatively short, maximum active survival being around 15-20 years. Older plants lose vigour, become top heavy and eventually keel over under their own weight and uproot themselves.
Vegetative reproduction
Vegetative spread of Gorse occurs by means of creeping roots, the species being capable of forming adventitious roots following major disturbances such as cutting of branches or of whole stems (Zabkiewicz & Gaskin 1978). Unfortunately, from the point of view of control or eradication of the shrub, both roots and shoots are also capable of re-sprouting after fire (Clements et al. 2001).
Fermanagh occurrence
Gorse is extremely common and widespread in Fermanagh, occurring in 417 tetrads, 79% of those in the VC. It is less frequent on limestone, but absent only from the highest ground, aquatic habitats and the best managed and most fertile farmland.
British and Irish occurrence and status
U. europaeus is very common and widespread throughout B & I, except on ground above approximately 640 m (D.A. Pearman, in: Preston et al. 2002).
Status in Britain and Ireland
Gorse is generally considered native in B & I, but all of the fossil records of the current interglacial period (known as the Flandrian in England and the Littletonian in Ireland) are from Zone VIIb or later and they are from settlement areas of Neolithic or younger date (Godwin 1975, pp. 177-8). It might be better, therefore, to regard it as a possible archaeophyte (ie an early, pre-1500 AD introduction). The close association of U. europaeus with disturbed sites, its known plantation for game cover or as hedging along roadsides, together with its many uses including as fodder and fuel, certainly indicates it is not naturally occurring everywhere in these islands. For instance, it is shown in the New Atlas as an introduction on the Isle of Man, Islay and Jura, the Outer Hebrides and in Orkney and Shetland.
European and world occurrence
Ulex europaeus was originally restricted to W Europe but it has spread to C & S Europe and N Africa. It remains most prevalent along the Atlantic coastline and near the Mediterranean basin, where it extends eastwards to mainland Greece. It has gradually spread northwards and eastwards from its native range in Europe and become naturalised and now occurs in southern parts of several Scandinavian countries (Tutin et al. 1968; Hultén & Fries 1986, Map 1185).
It is clear that the distribution of U. europaeus, like that of its relative, Cytisus scoparius (Broom), is very much governed by temperature. Gorse requires more or less oceanic conditions and it cannot survive in arid climates or in continental regions where there are seasonal extremes of heat and cold. Temperature also restricts the species to lower altitudes and while mature plants can tolerate quite severe frosts, in general they show a definite preference for habitats sheltered from cold winds. Day-length may also affect the latitudinal distribution of Gorse, as short-day conditions inhibit maturation of the plant and prevent both thorn formation and flowering (Zabkiewicz 1976).
Gorse has also been purposely introduced by man (eg for hedging, fodder or as an ornamental) to more than 15 countries or island groups throughout the world where maritime climates occur similar to that in its native distribution area,
including Australia, New Zealand, Chile, the Hawaiian Islands, Costa Rica and to both E & W coasts of N America (Hultén & Fries 1986, Map 1185; Clements et al. 2001). In the latter, for example, a few plants were brought into Marin County, California before 1912 as, "a bit of ol' Ireland" (Pryor & Dana 1952). In many of these areas of introduction, the plant remained localised and non-invasive, but after about 100-150 years residence in New Zealand, Tasmania and California, Gorse began to spread and it has now become a major weed problem, ousting native species from natural or semi-natural vegetation. Little (1960) commented that, "The invasion of New Zealand by this species is more spectacular than (that by) any other plant."
Fodder and other uses
Despite its spiny and intractable nature, U. europaeus is grazed by a variety of large herbivores and can be a valuable and highly nutritious source of fodder (Edwards & Ekins 1997). Much more could be made of this fact and a revival of this feeding practice should be encouraged since the necessary bruising treatment of cut gorse is very easily achieved. In past years, young plants were often severely grazed by rabbits, but the myxomatosis epidemics of the 1960s and later produced a prolonged rabbit decline, with the result that Gorse cover has often increased, especially in rough, ungrazed and more inaccessible ground (Grime et al. 1988, 2007).
Gorse hedges about Irish farmsteads were and still are much prized, not only for the shelter they afford to stock – they are dense and do not drip rainwater – but because they form an admirable clothes line on washing day and provide a ready source of kindling wood (Estyn Evans 1967, p. 42). Until the 1950s, young Gorse branches were fed to horses and other stock animals. Being so heavily spined, the branches were prepared by pounding them on knocking stones – flat slabs or stone basins where the shoots were 'melled' with a wooden mallet referred to as the 'whin-bruiser'. Alternatively, they were crushed by a large round, wheel-like grindstone on a long pole, powered by a donkey walking round a stone-lined 'course' as described by Ritchie (1930). These whin stones can sometimes still be found lying around old farmyards in Ireland and Scotland. There were even a few water-driven 'whin-mills' in Ulster, although as Estyn Evans (1957, p. 110) commented, "their use is almost forgotten, as is the custom of growing a field of whins to provide fodder. This was done in Co Cavan and it is a recognised method of land utilization in the poorer parts of Brittany."
A survey of the many and ingenious uses to which U. europaeus has been put in Ireland filled a 204 page book (Lucas 1960). The uses described by Lucas included: i. Fuel for various purposes. Since Gorse shoots contain a high concentration of oil, they make ideal kindling, but equally they pose a very real fire hazard in some sites. Gorse provides a quick hot blaze suitable for heating ovens and its use as fuel was common down to the 19th century and probably later and it was frequently traded for this purpose (Rackham 1986, p. 295). It was such an important source of fuel in some parts of B & I, that cutting of it was carefully shared and regulated in poorer communities (Mabey 1996, p. 230-2); ii. Construction – ie in roofing (as a framework for thatch), as bonding for mud walls and as a brushwood foundation for paths or roads across marshy or boggy ground; iii. Fencing, fodder and bedding for farm animals; iv. As brushes for brush-harrowing, a means of aerating grassland, or for cleaning chimneys or wells; v. As sticks for the Irish ball game of hurley, or for walking sticks; vi. For dyeing fabrics – giving yellows and brown. It was also used for colouring eggs at Easter (Lucas 1960; Mabey 1996).
Weed control
Since gorse is such a powerfully invasive woody weed of disturbed ground, capable of suppressing plantation forests and excluding grazing animals from pasture, there has been considerable research (especially in New Zealand) into improved methods of control using herbicides, grazing management (particularly successful when it involves goats or chickens) and fire, and various attempts at finding a means of biological control (Krause et al. 1988; Clements et al. 2001; Rees & Hill 2001). A very substantial body of research has been published and continues to grow on the whole subject of Gorse control. As an indication of the scale of this study, an annotated bibliography on the biology, ecology and control of gorse published 40 years ago ran to 266 citations (Gaynor & MacCarter 1981). In the search for a suitable agent for biological control, a survey was conducted of insects feeding on the shrub in its native European range. This found that many insect populations fed on the plant but did so at very low densities, so that gorse is scarcely affected by their presence. A rust fungus similarly attacks the plant quite frequently, but it does insignificant damage overall.
The current position regarding control of gorse recognises that a combination of control treatments is often required, eg laborious manual cutting, prescribed burning, or spot or broadcast herbicide treatment, plus reseeding with desired species, and/or carefully managed grazing, preferably using lightweight animals such as sheep and goats, since hoof damage of the soil surface by cattle or horses frequently provides gorse with ideal sites for fresh seed germination and re-establishment. A very useful and detailed review of the ecology of gorse and its control by Marc Hoshovsky is available on the Internet as an Element Stewardship Abstract of the Nature Conservancy, Virginia, USA at http://tncweeds.ucdavis.edu/esadocs/ulexeuro.html (viewed May 2021).
Names
The genus name 'Ulex' is Latin and originated from the pen of the ancient Roman writer Pliny. However, all we know is that it was a name he applied to a shrub, possibly spiny, possibly ericaceous and, by another source, said to resemble Rosemary (Gilbert-Carter 1964; Hyam & Pankhurst 1995). The Latin specific epithet 'europaeus' is purely geographical and this time the current author (RSF) will not insult readers by offering to translate it!
English common names are rather plentiful, Britten & Holland (1886) listing 25: however, many of them are related and fall into categories. The three most common are 'Gorse' (from the Anglo-Saxon or Old English 'gorst'), Furze (Old English 'fyrs') and 'Whin'. The latter is conjectured to be from Old Norse 'hvin', partly because it appears in place names in the N & E of England, eg 'Whinburgh', in Norfolk, and it is the English common name most frequently applied in the Scandinavian influenced parts of B & I (Grigson 1974). A dialect variant of it is 'Whuns' (Britten & Holland 1886).
'Gorse' is possibly derived from 'Gorst', or in Welsh, 'Gores' or 'Gorest', all words meaning or referring to 'a waste', ie perhaps because the plant frequently grows on disturbed or waste ground. Other spellings are 'Gorze' 'Gost' and 'Goss' (Britten & Holland 1886). 'Gorse' might alternatively be derived from the Medieval Latin 'gorassi' or 'gorra', meaning, 'brushwood', since fire making was often the major use of the species (Prior 1879).
'Furze', sometimes spelt 'Furres', or more rarely 'Furre', or 'Furrys' (or in dialect variants, 'Furzen', 'Furzen Bushes', 'Fuzz', 'Fuz', 'Fuzzen', 'Furra', 'Frez', 'Firsun', or even 'Vuzz', 'Vuz' or 'Vuss') is the most commonly used name for Ulex europaeus in Ireland and in SW England (Britten & Holland 1886; Grigson 1987). It appears to have come from the Anglo-Saxon or Old English 'fyrs', a word described by Prior (1879) as, "of obscure derivation, as are those of so many of our commonest plants". Both Prior and Grigson (1974) suggest the name is in some way related to 'fir' (or in Old English 'fyrh' or 'furh'), meaning 'a fir-tree', the implication again possibly being that Furze, like the coniferous fir tree, was a very common firewood or fuel and thus the name carries the same fire making connotation as Medieval Latin 'gorassi' and 'gorra' does for 'Gorse'.
As if these names were insufficient, U. europaeus has also been referred to as 'Thorn Broom', 'Prickly Broom', 'Fingers and Thumbs' (Wiltshire), 'Thumbs and Fingers' (Somerset) and 'Pins and Needles', all presumably on account of its spiny-ness.
Several other names given to U. europaeus suggest an association with different spine-armed plants, such as 'Hawth' or 'Hoth' (perhaps a mental link with Crataegus monogyna (Hawthorn)?) and 'Qwyce' or 'Quyce', perhaps suggesting the neophyte Quince (Chaenomeles speciosa (Sweet) Nakai and C. japonica (Thunb.) Lindl. Ex Spach), although these were only introduced in 1796 and 1869 respectively. Further names given by Britten & Holland (1886), which cannot be rationalised in this way, are 'Ruffet', 'Turr' and 'Ling', the latter a name widely applied to numerous heathland plants, but almost always to members of the Heather family.
Names like 'Great Furze' and 'French Furze' appear to be used to distinguish the different species of Ulex, ie separating U. europaeus from the much smaller U. gallii and U. minor, or perhaps more likely, just the differing ultimate sizes of these plants.
Folklore
As one might expect of such a prominent landscape plant with so many folk uses, Gorse has numerous attached folklore beliefs and it was sometimes pressed into medicinal services also, eg for jaundice (on account of its yellow 'signature'), against snake bite and as an insecticide (Vickery 1995). Grieve (1931) mentions that an alkaloid was obtained from the seed which had a powerful purgative action. However, it turned out to be chemically identical to one obtained from Cytisus scoparius (Broom).
Threats
No threats to it, but it is so invasive it can itself become a weedy pest, especially when it is introduced abroad, eg to New Zealand.