Field Gromwell (also known as corn gromwell) is an annual with an erect, slender stem sometimes surrounded by several smaller stems that branch of from the base.
The flowers occur in the leaf axils of the reduced upper leaves. They are bluish white, five lobed and about 5-8mm wide. The flowers, which are in bloom from April to September, are followed by grey-brown warty nutletes. The seed within the nutlet is extremely hard and stony hence the old generic name Lithospermum.
Field Gromwell is a native annual of continental Europe and northern Asia becoming established here with the rise in agriculture. Archaeological evidence shows it has been an arable weed in Britain since at least the Bronze Age. It is still most commonly associated with arable fields but can also be found on waste ground and other disturbed habitats particularly on lighter, calcareous soils.
With the increase of agricultural intensification following the war, field gromwell has been in steep decline, however this situation may soon change. It has recently been discovered that field gromwell’s seeds are extremely high in omega-3 and omega-6 fatty acids, both essential nutrients for humans, and trials are now underway to see if it can be grown as a crop.
Best sown in the autumn. The seed is relatively short-lived in the soil so the ground needs to be disturbed annually if the population is to persist.