Merwilla plumbea (Scilla natalensis) is a graceful perennial bulb, and with its tall plumes of blue flowers, the showiest of the South African scillas. It is deciduous, growing during summer and dormant in the winter. It can grow up to 1 m tall, often in large colonies on cliffs and rocky slopes. Widespread in eastern summer rainfall areas.
A rosette of 6 to 9 broad, tapering leaves emerges from the top of the bulb in spring. The leaves are attractive in their own right, with clearly distinct veins which give them a two-tone effect, particularly when back-lit. Their colour is light green with white-grey overtones, they can be entirely green, or they can have purplish colouring on the margins, at the base or at the apex of the leaf, or the underside can be partially or entirely shaded with purple. They can be completely hairless, or one or both sides can be covered in short hairs. The leaves of a well-grown plant can reach a height of 30 to 50 cm with about equal spread.
The ash from a burnt plant, and the bulb in powdered form, is rubbed into cuts and scratches, and over sprains and fractures. Decoctions are taken as enemas for female infertility and to enhance male potency and libido. It is also known to be used as a purgative, a laxative and for internal tumours, and is used in conjunction with other ingredients in infusions taken during pregnancy to facilitate delivery and in treatments for chest pain and kidney troubles. It is also an ingredient in a medicinal preparation for cattle suffering from lung sickness. It has magical properties for the Tswana who rub the powdered bulb into the back, joints and other body parts to increase their strength and resistance to witchcraft. The plant appears to have significant analgesic and antimicrobial activity, and phytochemical studies have found that it contains compounds known to possess anti-inflammatory and anti-mutagenic properties which would support its use for the treatment of strains, sprains and cancers.
Merwilla plumbea has shown itself to be selectively toxic to mammals. It is said to be poisonous to stock, particularly when the young leaves appear in spring. Experiments on sheep, using fresh bulb as a drench, proved fatal to the sheep, yet it has been proven an ineffective rat poison. It is apparently toxic to man when raw, even the sap is reported to burn the skin, and for any preparations taken internally the plant must first be heated. This plant should be treated with extreme caution, as taking any part of it internally is potentially fatal.
What is in a name?
Merwilla plumbea is the name given to a combination of several species, namely S. kraussii, S. natalensis and S. plumbea. This description pertains primarily to the form previously known as Scilla natalensis. This genus has been named after F van der Merwe, a botanist who worked on this family. The species name refers to the lead blue colour of the flowers.
The Afrikaans name blouberglelie, which means blue mountain lily, is also applied to other South African species of Scilla and is a name that has been in use for hundreds of years. It earned the name blouslangkop, which means blue snake’s head, presumably because the emerging flower stalk resembles a snake, and the tips of the flower stalks are often coloured bluish-purple. The Zulu name inguduza means “searching the body for the cause of the ailment”, indicating its use in KwaZulu-Natal as a diagnostic tool.
Photos: Joan Keyter