Isatis tinctoria, from its Latin name, is a biennial with taproot rustic en zone 4. This brassica is found in the wild in South-Eastern Europe, Central and South-West Asia, as well as in northern Africa.
- The edible leaves must first soak in water for several hours to rid them of excess bitterness. We then prepare them like rocket.
In France, pastel generally bears the name wad, but the Normans call it voude, the Picards, wait and the inhabitants of the north of the country, wedde. It was also named Saint-Philippe grass, varède et Lauraguais grass. In China, it is called sunglan.
The ancient Greeks and Romans used it extensively to treat et dye tissues.
Moreover, the botanical name given to the genus by Linnaeus in 1753 derives from the Greek isazein which means “to flatten”, because the plant was used for healing wounds.
Photo credit : PD (Public Domain); Nationalmuseum's collections; “Carl von Linné, 1707-1778, botanist, professor”
- Dyers’ pastel has vertus antibacterial, antiviral, astringent and anticarcinogenic. It is used, among other things, for the treatment of edema, tumors, scurvy, spleen diseases, influenza, fevers, pneumonia and several infectious diseases.
En traditional Chinese medicine, its root is used to evacuate toxins from the blood and treat, among other things, cases of fever, flu, meningitis, abscesses and skin infections. Its leaf is indicated for delirium and loss of consciousness, as well as dry and irritated throat.
- In China, its dyeing is very popular for coloring silk and cotton.
- In the East, it is mixed with henna to dye hair.
- The Japanese used it to dye the paper used for book covers.
- In the United States, dyers’ pastel is classified “ invasive plant undesirable » in the west of the country.
His culture
Dyers’ woad is grown in full sun, in well-drained soil which can be rich or poor. Its favorite sites are the rather calcareous and clayey soils found in wastelands, along roadsides and in rocky terrain.
Firstre year, the sowing produces a rosette of slightly bluish green basal leaves. At his 2e year, yellow flower stalks up to 1,5 m high rise above the foliage in June.
- Its small flowers which quiver in the slightest wind are very popular with bees and other pollinating insects.
After flowering in early summer, the plant remains attractive. The winged seeds contained in dark brown siliques 1 to 2 cm long fall to the ground when ripe to ensure the sustainability of the species.
This thermophilic plant requires high heat to live and reproduce and summers that are too cool can inhibit seed formation. If seed production fails, the rosette returns the following year to try its luck at reproducing once more.
