Up to 5 feet.
The plant is rich in luteolin, a flavonoid which produces
a bright yellow dye.The yellow could be mixed with the
blue from woad (Isatis tinctoria) to produce greens such
as Lincoln Green. The dye was in use by the first
millennium BC. Use of this dye came to an end at
the beginning of the twentieth century, when
cheaper synthetic yellow dyes came into use