Wild B. olearacea is a tall biennial plant, forming a stout rosette of
large leaves in the first year, and stored nutrients are used to produce a
flower spike 1–2 m tall bearing numerous yellow flowers in the second
year.
The roots can be found up to 3 feet away from the plant. After a few
months of growing some of the roots will mine vertically to a depth of
1.5-2 m.
The stem is waxy, usually unbranched and, from it arise the leaves and
flower heads.
The leaves are simple, alternate and without stipules. Many times they
are pinnately lobed.
