St Benedict’s Thistle, Centaurea benedicta, is another of those plants which has received a lot of attention from taxonomists, so you may find it labelled as Carbenia benedicta, Carduus benedictus or Cnicus benedictus. Other common names by which it is known include bitter thistle, blessed thistle, cardin, holy thistle and spotted thistle.
It shares the names blessed thistle and holy thistle with the milk thistle, but it is quite easy to tell them apart, even when neither is in flower, as you can see by just comparing the photograph on this page with the one on the previous post. The milk thistle has leaves which are marked along the veins with a milky color, whereas the St Benedict’s thistle does not.
St Benedict’s thistle is a hardy annual which reaches a height of around 2 feet, native to Southern Europe and Western Asia. It requires well drained soil and will not grow in shade but is otherwise unfussy as to situation. Because of this it has become known as a noxious weed in parts of the world where it has been introduced, including North America. It may therefore be best to grow it in containers, and to remove flowers before they turn to seed.
The root and flower buds of St Benedict’s thistle are edible – the flower buds like tiny globe artichokes and the roots boiled as a vegetable.
St Benedict’s thistle should not be used by pregnant women (especially in the first trimester) or those trying to become pregnant.
Once seen as a cure-all, St Benedict’s thistle is less often used nowadays, though it has a wide range of applications. It is used internally as a herbal tonic; to treat anorexia; to promote appetite in cases of depression; for many digestive disorders including indigestion, colic and flatulence (“gas” or “wind“); to stimulate the gall bladder and treat disorders of both gall bladder and liver; to promote milk production in nursing mothers (recommended by the Canadian Breastfeeding Foundation); to promote menstruation; to promote sweating; and in large doses to induce vomiting. Externally it is used to treat wounds and external ulcers.
For all these uses, make a standard infusion using 30g (1 ounce) of chopped herb to 600ml (2.5 US cups, 1 UK pint) of boiling water; leave to stand for 15 minutes to 4 hours, then strain off the herb and discard. Do not sweeten. Use the infusion warm for promoting lactation. The dose is half a cup sipped slowly up to 3 times a day, which should be increased if the intention is to induce vomiting.
As with all herbal remedies, care should be taken to avoid using man-made chemicals on these plants so as to ensure that the active ingredients are not corrupted by them. As a thistle, there is no need to fertilize in any case, and it is unlikely to be seriously attacked by predators in a well stocked garden. To find out more about growing organic St Benedict’s Thistle visit the Gardenzone.