What is isatis Indigotica?

What is isatis Indigotica?

Isatis indigotica is an herb distributed widely in China and traditionally used in clinical treatment of viral diseases like influenza, hepatitis, and encephalitis [1, 2].

How do I get rid of Dyer's woad?

Cutting off the blooms before they turn to seed will minimize the spread of woad. Sowing weed-free seed and feeding livestock with weed-free hay can also help reduce the impact of the plant. In some situations, repeated tilling of an area is an effective way of getting rid of woad.

Does woad grow in Ontario?

In the 1830's, woad was listed in the seed catalogues in Ontario, as the plant was common in household gardens. ... It began in a 1900 contamination of Alfalfa Seed in Calilfornia, which got away. This is the woad being used today by natural dyers in North America.

How do you make woad?

Take the leaves from the base of the plant and then cut them into small pieces. Submerge the torn or cut leaves in a stainless steel pan of water and bring up to a temperature of 175F (80C). Simmer for about 10 minutes. Cool the woad dye down as quickly as possible, so that the leaves don't breakdown too much.

Why was blue pigment so expensive?

In China, copper was blended with heavy elements such as mercury to create shades of blue. So new and exciting were the colours created that they were attributed healing qualities and mixed into poisonous “medicinal” concoctions. ... Wherever it came from, blue pigment remained costly to produce.

Is Blue really a color?

There was no blue, not in the way that we know the color — it wasn't distinguished from green or darker shades. ... If you think about it, blue doesn't appear much in nature — there are almost no blue animals, blue eyes are rare, and blue flowers are mostly human creations.

Why is the color blue so rare in nature?

Blue is a very prominent colour on earth. But when it comes to nature, blue is very rare. Less than 1 in 10 plants have blue flowers and far fewer animals are blue. ... For plants, blue is achieved by mixing naturally occurring pigments, very much as an artist would mix colours.