Good post from 2005 on chicory over at the Bookish Gardener. B would love to grow this in our garden because the flowers are so pretty. I’d never considered doing that for some reason, though I love the flowers, too. They’re a clear true blue. I’d always (ignorantly) assumed we’d have to dig it up from beside the road or from the unmowed meadow to get it.
So I did dig some up in midsummer (when I could actually identify it by the blooms). The roots were brittle, the plants wilted immediately, and I never saw them again.
It is possible, of course, to acquire some seeds (Cichorium intybus or Cichorium endivia) and simply sow them. As we used to say in high school: Duh.