An erect, deciduous shrub of open scrub on dry, calcareous grassland overlying chalk or limestone. Populations often consist of only a few individuals. Lowland.
This species was neglected for many years; recorders have only recently become familiar with it and its distribution is not yet fully documented. It has been lost from some sites due to ploughing, and from others through a reduction in grazing leading to over-shading. However, new sites continue to be found (there were recent records from 16 10-km squares in Britain in Wigginton, 1999), and more doubtless await discovery. In Ireland, its distribution appears to be better known and more stable, but even there it is probably under-recorded.
European Temperate element.
Light (Ellenberg): 8
Moisture (Ellenberg): 3
Reaction (Ellenberg): 8
Nitrogen (Ellenberg): 3
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 4.1
July Mean Temperature (Celsius): 15.6
Annual Precipitation (mm): 836
Height (cm): 150
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 55
Count of 10km squares in Ireland: 39
Count of 10km squares in the Channel Isles: 0
RDB Species Accounts
Rosa agrestis Savi (Rosaceae)
Small-leaved sweet-briar, Miaren Gulddail
Status in Britain: LOWER RISK - Nationally Scarce.
Status in Europe: Not threatened.
The principal habitat of R. agrestis is open scrub on dry calcareous grassland, which is also the habitat of a number of other Rosa species. R. agrestis is a free-standing, erect shrub with slightly flexuous stems. It is rather inconspicuous, with no striking features to make it obvious from a distance, and is apt to occur as single isolated individuals rather than in large stands. For these reasons it can be easily overlooked in the presence of other Rosa species, which may sometimes be abundant in this habitat, especially R. canina which when young and growing free-standing may have a habit very similar to that of R. agrestis.
Only recently has the taxonomy of the British Rosa species been placed on a sound basis (Stace 1991; Graham & Primavesi 1993). Before this, few people took a serious interest in the genus, and therefore authenticated records for even the commonest taxa are few. Our knowledge of the status of R. agrestis is consequently incomplete. Since 1970, it has been recorded from only about thirteen sites on the chalk in southern and south-east England, with outlying records from Somerset, Dorset, Worcestershire, Norfolk and Caernarvonshire. Older records, supported by herbarium vouchers, confirm its mainly southern distribution, though there is a single apparently anomalous record from Northumberland.
The future of R. agrestis depends largely upon the permanence of its habitat. Much of this type of open scrub has recently gone under the plough or has been diverted to other uses. Furthermore, it is a stage in succession leading to a climax vegetation, usually woodland, and its stability depends upon the activities of man or grazing animals. Total neglect and lack of grazing would, in time, be detrimental. The first great epidemic of myxomatosis, with a severe reduction in the rabbit population, showed how rapidly scrub became dense and impenetrable, in which state R. agrestis would ultimately be shaded out. Notwithstanding the need for grazing to control scrub, young plants of R. agrestis must survive the predation of grazing animals. The climbing species of Rosa are probably less susceptible to this predation because they are partially concealed and protected in their seedling stages by the plants up which they climb. The rather blunt prickles of R. agrestis may provide less of a defence than do the fiercely-hooked prickles of R. rubiginosa, which is also characteristic of open scrub.
R. agrestis is widespread in Europe, becoming rarer northwards and absent in the extreme north (Klástersky 1968). It is likely that careful survey in Britain would reveal further sites within its historic range, though it is probably a truly uncommon species. It may be significant that its apparent greater frequency in similar habitats in central Ireland reflect the thoroughness with which a keen local botanist has scoured that country with a critical eye.
Because of the comparative rarity of R. agrestis, its hybrids with other species appear to be correspondingly rare. Authenticated records, mostly from old herbarium material, are only about ten in number, including hybrids with R. stylosa, R. canina, R. sherardii and R. micrantha.
A. L. Primavesi