coast fiddleneck, Menzies fiddleneck, small-flowered fiddleneck, tarweed
Amsinckia micrantha Suksd. (A. calycina, A. intermedia, A. menziesii)
Common fiddleneck or tarweed is an introduced annual weed. It is locally frequent in eastern England especially as a cornfield weed in the Breckland area of East Anglia, where it seems to be increasing. It belongs to the borage family and has the appearance of a yellow-flowered bugloss. Common fiddleneck is a native of North America where it flourishes in disturbed areas on roadsides, neglected fields and on poor grade pasture. It was recorded as naturalised in the UK in 1910 and was thought to have been introduced as a seed impurity, although, it had been cultivated here since 1836. In East Anglia it was first noted early in the 1900s in old chicken runs. It was also recorded from waste ground in southern England and as a local weed in Bedfordshire and elsewhere. In a survey of arable weeds 1971-1973, it was recorded in arable situations and roadsides but was found in less than 2% of the areas surveyed. In a study monitoring arable field margins in East Anglia 1989-1996, common fiddleneck was one of the most frequent species in some areas. Common fiddleneck is considered an indicator species of low summer moisture and disturbed light soils.
Common fiddleneck is found in flower from May to July and flowering may continue into October. The flowers are self fertile and usually self-pollinated. Each flower produces 4 seeds loosely enclosed in an expanded bristly calyx. The flower spike is compact initially but it elongates as the flowers develop and becomes crosier-like, hence the name fiddleneck. New flowers develop at the apex of the flower spike as the older flowers mature. The seeds in the lower flowers ripen and the hard black seeds loosen and fall out when mature.
There is no obvious dispersal mechanism but the seeds, still enclosed in the bristly calyx, are often dispersed on the fur of animals. Common fiddleneck seed has been introduced to new areas as a contaminant in sandy soil brought in from elsewhere. Where this has occurred, seedling emergence has continued intermittently for several years. There are suggestions that the seed has been introduced in poultry feed and may persist in bird droppings.
No information has been found specifically on the control of common fiddleneck. It should therefore be managed as any other annual weed would be by shallow cultivations to kill emerged seedlings and prevent seeding.
Updated November 2007.