Sulphur clover
9 August 2010
As its name suggests, the Sulphur clover is distinguished by its showy upright flower heads of pale yellow flowers. Once a characteristic plant of meadows and unimproved pastures on chalky boulder clay in East Anglia, it has been all but banished to road verges and railway banks, where it is vulnerable to disturbance and inappropriate management.
Sulphur clover © Kevin Walker (BSBI)
Latin name: Trifolium ochroleucon
Population numbers:
Sulphur clover is now a nationally scarce plant, recorded recently (since 1987) in only 76 10km squares. Whilst it is still locally abundant in some protected meadows and road verge reserves, it has suffered a severe decline across its range. Large areas of its grassland habitat have either been converted to arable or have lost their botanical interest due to grassland ‘improvement’ or the cessation of traditional management. Many roadside sites have been destroyed as a result of road-widening and re-routing schemes. A resurvey of populations in Huntingdonshire showed a loss of over half, 57%, since the 1960s, principally due to reduced management of habitats such as road verges, green lanes and woodland rides and agricultural improvement of meadows and pastures.
Where to see and when:
Sulphur clover is probably most abundant on road verges in North Essex around Uttlesford but may also be seen at Upwood meadow NNR in Cambridgeshire. Look out for its sulphur yellow flower heads, which fade to brown as seeds ripen, and spreading rosette of grey-green leaves at the stem base. Flowers may only be apparent for a few days in June or July, the timing depending on the weather in any one year
What’s being done:
Sulphur clover populations are thriving due to good management and a number of meadows statutorily protected by Natural England. In addition many, but not all, of its roadside verge populations are recognised by the relevant County or District council as Protected Roadside Verges due to their biodiversity interest. These special verges are marked with wooden posts at either end, with a white plaque warning contractors that the area within the posts is specially protected and no dumping or unauthorised management should occur. Whilst all road side verges must have a safety cut in May/June to ensure visibility to motorists , Protected Roadside Verges receive additional cuts at other times of year to benefit particular plants or insects.
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