Isatis tinctoria, also called woad, dyer's woad, or glastum, One of my favourite plants as it smells divine, attract many bees and other insects, is easy to grow, very very useful as a dye (blue) or as a medicine for the flu. Easy to grow. Biennual. Leaves the first year and flowers the second. Amazing seed heads for flower arrangers too. Quite tall, 1m or higher.
Easy to grow and will self seed where it wants to, not invasive. . approx 20 seeds