Taxonomic name: Cytisus scoparius (L.) Link
Synonyms: Genista scoparius (Lam.)., Sarothamnus scoparius (L.) Wimmer ex Koch, Spartium scoparium (Linn.).
Common names: Besenginster (German), broomtops (English), common broom (English), European broom (English), genêt à balais (French), giesta (Portuguese), Irish broom (English), Scotch broom (English)
Organism type: shrub
The densely growing Cytisus scoparius is a shrub indigenous to Europe and northern Asia that favours temperate climates and is found in abundance on sandy pastures and heaths. It is sparingly naturalized in sandy soil in North America. It grows best in dry, sandy soils in full sunlight and can also do well on soils high in boron. Where introduced, it colonizes pastures and cultivated fields, dry scrubland and "wasteland", and native grasslands. Most rapid spread of the plant has occurred along waterways where the seed is distributed by water. It is also spread rapidly along roads, where the seed is distributed by passing vehicles. Wind, birds, and other animals may also transport seeds. Seed re-introduction may occur from the sheep droppings during grazing.
Hoshovsky (1986) reports that is a perennial shrub of the Fabaceae (Leguminosae) family. The shrubs are 1-2 metres high and deciduous. The green branches are strongly angled and appear naked or almost so. The leaves are trifoliolate with petioles 2-10mm long. The leaflets are obovate to oblanceolate, entire, strigose, and 6-12mm long. Unlike Cytisus monspessulanus (French broom) and Spartium junceum (Spanish broom), the yellow flowers of C. scoparius are usually borne solitary in axils. The glabrous banner is ovate to rounded; wings are oblong to ovate; and the keel is straight or curved. Petals are about 2cm long. The flaring calyx is glabrous, about 7mm long, and two-lipped with short teeth. The brownish black pods, 3.5 to 5cm long, are villous on the margins only. These pods are compressed, several seeded, and have a callous appendage or strophiole near the base.
agricultural areas, range/grasslands, riparian zones, ruderal/disturbed, urban areas, water courses
C. scoparius grows best in dry, sandy soils in full sunlight and will grow well in soils with pH values ranging from 4.5 to 7.5 (Gill and Pogge 1974, in Hoshovsky, 1986). In Europe it is found on moderately leached soils in heathlands, acidic grasslands, and inland dunes (Bicher and Larsen 1958, in Hoshovsky, 1986). It can also do well on soils high in boron (Vergnano 1957, in Hoshovsky, 1986). C. scoparius grows in more sheltered habitats (Davies et al. 1978, in Hoshovsky, 1986). Where it has been introduced, it invades pastures and cultivated fields, dry scrubland and "wasteland", native grasslands, and along roadsides, dry riverbeds, and other waterways (Gilkey 1957, Johnson 1982, Williams 1981, in Hoshovsky, 1986). It does not do well in forested areas but invades rapidly following logging, land clearing, and burning (Hoshovsky, 1986).
Hoshovsky (1986) states that C. scoparius' abundant production of long lasting viable seeds, aggressive spread, and establishment away from planted areas into stands of native vegetation causes it to be of serious concern. It prevents reforestation, creates a high fire hazard, in the United States renders rangeland worthless, and greatly increases the cost of maintenance of roads, ditches, canals, and power and telephone lines. In North America wildlife also suffers as the growth becomes too dense for quail to thrive and chokes out forage for deer. C. scoparius is slightly toxic and unpalatable to livestock, so it is very poor browse.
Hoshovsky (1986) cites that C. scoparius has been used for a variety of purposes throughout European history, beyond its use for sweeping floors. An infusion of the leaves was used as a diuretic. Bark shavings were used to stop the flow of blood in the 14th century. A salve was made from the blossoms. The tops of broom were put in beer to give it a bitter taste. Some people have used the seeds to "adulterate" coffee. The flowers in bud are pickled like capers. It is cathartic and the seeds cause vomiting. Broom has been used for thatching, fencerows, and cattle fodder. The woody plant was once used for tanning leather and the old wood for veneering. Cloth has been manufactured with the fiber. C. scoparius was sold as an ornamental in California in the 1860's.
C. scoparius stands provide a more suitable environment for later successional species than gorse (Ulex sp.). It is leafless from late summer to early spring, allowing light to reach seedlings of later seral species. It produces a sparse, readily decomposable litter, unlike the acidic litter of gorse (Williams 1983, in Hoshovsky, 1986).
Analysis of the results of a study (Sheppard et al. 2002), conducted to study factors affecting invasion and persistence of C. scoparius in Australia indicated that the presence of competing vegetation has little effect on C. scoparius regeneration.
For more details please see ConservationEvidence.com, Case study 99: The effect of soil disturbance, grazing and ground cover compositon on the expansion of an invasive plant, broom Cytisus scoparius, in the Southern Tablelands of New South Wales, Australia. [extracted from: Sheppard A.W., Hodge, P. Paynter Q. and Rees M. 2002 factors affecting invasion and persistence of broom Cytisus scoparius in Australia. Journal of Applied Ecology 39, 721-734].
Native range: Hoshovsky (1986) states that C. scoparius is native to the British Isles as well as central and southern Europe.
Known introduced range: It first became naturalized in North America on the east coast (Mountjoy 1979, in Hoshovsky, 1986) and is found in Nova Scotia, New York to Georgia (Gill and Pogge 1974, in Hoshovsky, 1986), and parts of the upper Midwest (USDA-NRCS, 2002). It became naturalized on Vancouver Island (Bailey 1906, in Hoshovsky, 1986) and was probably planted throughout the Pacific Northwest as an ornamental. Hoshovsky (1986) states that in the west it has now become established along the inland valleys of the Pacific Northwest from British Columbia to central California. It is also found in New Zealand (Hoshovsky, 1986) and northern Asia (Grieve, UNDATED). Its northern limits are probably dictated by low winter temperatures and the southern limits by summer drought (Hoshovsky, 1986).
Introduction pathways to new locations
Floating vegetation/debris: The most rapid spread of the plant has occurred along waterways, where the seed is distributed by water (Hoshovsky, 1986).
For ornamental purposes: C. scoparius was sold as an ornamental in California in the 1860's (Hoshovsky, 1986).
Road vehicles (long distance): There has been a rapid spread of this weed, often for long distances, along roads where the seed is distributed by passing vehicles--often in gravel hauled from river bottoms (Hoshovsky, 1986).
Local dispersal methods
Consumption/excretion: While sheep are valuable for weed control, it is possible that seed re-introduction may occur from the sheep droppings (Hoshovsky, 1986).
On animals (local): Pods often open explosively, especially in a drying wind, and the seeds may be widely scattered (Hoshovsky, 1986).
Other (local): Seeds may also be transported by birds and other animals to isolated areas (Hoshovsky, 1986).
Water currents: The most rapid spread of the plant has occurred along waterways where the seed is distributed by water (Hoshovsky, 1986).
Preventative measures: Hoshovsky (1986) states that soil disturbance should be kept to a minimum as it provides bare soil, which is very conducive to broom seedling establishment. Improper use of broadcast burning may contribute to a re-invasion. Planting of tall, growing shrubs or trees in or near C. scoparius stands may aid in reducing photosynthesis and possibly lead to their demise.
Sowing native plant species which have the potential to out-compete weedy exotics for important resources is usually a preventive method of weed control. In some cases later successional plants may be encouraged to take root among the unwanted vegetation. C. scoparius stands provide a good environment for the establishment of other broadleaved shrubs or trees. Such seedlings should be looked for in the stands and encouraged. In addition, seeds of taller growing plants should be sown among this weed.
For details on chemical, physical and biological control options, please see management information.
Hoshovsky (1986) states that it can tolerate low soil temperatures and can fix nitrogen throughout the year in regions with mild winters.
Hoshovsky (1986) reports that C. scoparius may reproduce vegetatively or by seed. It has been purposefully propagated from cuttings (Gill and Pogge 1974, in Hoshovsky, 1986), and it sprouts back after cutting (Mountjoy 1979, in Hoshovsky, 1986). It can produce up to 60 seedpods per bush by its second year. Each pod usually contains 5-8 seeds (Waloff and Richards 1977, in Hoshovsky, 1986).
Seedlings buried more than 10cm deep fail to emerge (Hoshovsky, 1986). The fastest emergence occurs when seeds are buried less than 3cm deep in a fine textured substrate (Williams 1981, in Hoshovsky, 1986). Hoshovsky (1986) states that the seedlings may be damaged by frost, but this has little direct effect on their total height growth in their early years. Six to eight years of growth is followed by degeneration accompanied by an increase in the ratio of woody to green material, reduction in seed production, and finally death. They rarely live more than 10-15 years (Waloff 1968, in Hoshovsky, 1986).
Reviewed by: Dr P.J. Bellingham. Landcare Research. New Zealand.
Compiled by: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)
Last Modified: Thursday, 23 March 2006