Lapathum venosum (Pursh) Lunell
Common Name: Sour Greens
Rumex venosus is a perennial plant wwith creeping rhizomes; the ascending, occasionally erect stems can grow around 15 - 40cm tall[
The plant is harvested from the wild for local use as a food, medicine and source of materials.
Plants can contain quite high levels of oxalic acid, which is what gives the leaves of many members of this genus an acid-lemon flavour. Perfectly alright in small quantities, the leaves should not be eaten in large amounts since the oxalic acid can lock-up other nutrients in the food, especially calcium, thus causing mineral deficiencies. The oxalic acid content will be reduced if the plant is cooked. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition[
Western and central N. America - Alberta to Manitoba, south to California to Texas
Sand dunes, sandy and gravelly riverbanks and slopes, deserts, grasslands at elevations from 200 - 1,500 metres[
Species in this genus generally succeed in a variety of soils, but they prefer deep fertile moderately heavy soils that are humus-rich, moisture-retentive and also well-drained, with a position in full-sun or part shade[
Being wind -pollinated, Rumex species usually hybridize readily, especially with other members of the genus they are more closely related to[
Young leaves - cooked[
]. Used as greens.
Young stems - cooked[
]. Used like rhubarb[
The root is astringent, blood purifier and tonic[
]. A decoction has been used in the treatment of diarrhoea, coughs and colds, influenza, pneumonia, stomach aches, kidney disorders, gall bladder problems, venereal disease and rheumatism[
]. An infusion has been given to women to help them expel the afterbirth[
The root can be dried, ground into a powder and used as a dressing on burns, wounds, sores etc[
]. A poultice can also be made from the fresh root for use on burns, wounds, sores, swellings etc[
An infusion of the stems and leaves has been used as a wash on sores[
A yellow dye is obtained from the root[
]. The roots are peeled, broken into sections about 25mm long, then spread out thinly in a sunny position until very dry. They are then soaked in water for a few days before being boiled in the same water for a long time. Alum is then added to fix the colour[
]. A red dye is obtained if ashes are added and it turns black if the bark of Cornus stolonifera is also added[
Seed - sow spring in a cold frame. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer.
Division in spring.