Blessed Thistle (Carduus benedicta or Cnicus benedictus) is also known as holy thistle, Benedict’s thistle, bitter thistle, cardo santo, lady’s thistle and other names. Its scientific name “Benedictus” is Latin for blessed, since this plant has a reputation of being able to cure it all. The curative properties were considered to be a gift from God. Blessed thistle’s medicinal benefits are so immense that it was even remedy from the Black Plague during the Middle Ages.
Today it is commonly used for menstrual problems and to promote lactation for breastfeeding mothers. It is also used as a digestive and liver aid, as well as a blood purifying tonic.
How Does Blessed Thistle Look?
This herb is quite beautiful, making it a great addition to your flower garden. Blessed thistle is a hardy annual that is native to the Mediterranean, from Portugal to France and east to Iran. It is cultivated in the United Kingdom and some parts of North America, where it is often considered to be a weed.
It is a free branching plant with toothed leaves that have spines. Reddish stems are fairly slender with mild dull green color leaves that are long and narrow. Leaves have a central vein and irregular wavy margins. All parts of the plant, including stems, leaves and flower heads have a light down covering.
This plant grows between 20-24 inches in height. It has a sprawling and prostrate habit instead of standing upright. Blessed thistle will bloom from mid summer to early fall, producing typical thistle flowers. It will flower until the first hard frost.
There is a confusion with the name of this plant, since it is sometimes listed as Centaurea benedicta, which some sources say is a reclassification of the plant. However, photos show upright plants with purple flowers that are not this plant. Unlike other species of thistle, such a milk thistle, this plant does not produce purple or pink flowers. Flowers are yellow in the center with long surrounding reddish spikes that look like a crown of thorns.
How to Grow Blessed Thistle?
It is best to sow seeds outside in spring, just after the danger of frost is gone. Seeds are too large for most seed trays. Those who would want to sow seeds inside will have to do it by placing one seed per pot.
Place seeds 1/4 of an inch in the soil which should stay moist until germination which can take between two to three weeks. Stratify seeds at a temperature of 39 F (3 C) for a month if they do not germinate in that period. Make sure to leave a space of at least 12-15 inches between plants.
This thistle grows well in USDA zones 5 through 9. 70 F (21 C) is the ideal temperature for this plant. Those who live in zones 8+ can sow seeds outside late fall, since they will germinate producing a rosette which will overwinter and then grow in the spring.
Blessed thistle grows best in full sun. Soil must have good drainage; this plant will die in waterlogged soil, as it likes rocky and poor soils. It is quite drought tolerant after being established, but it will not produce lush leaves unless it gets some water daily.
How to Harvest and Use Blessed Thistle?
Those who want to eat this variety of thistle should harvest young tender leaves. These leaves can be dried to make tea. Harvest leaves before the plant flowers. Please note that eating too many leaves will make you throw up. Plants can be cut by 1/3, up to two or three times per season. Roots are also edible; as they can be boiled like a vegetable.
Flowering tops, upper stems and leaves are all used to make medicine. Allow the plant flowers to go to seed if you want it to re-seed the following year. You can also gather and store the seeds. Be nice and leave some for the birds who enjoy them as well. There are many blessed thistle supplements, including powder, pill and tinctures.