Can you identify this plant? We have moved into a new house, and this plant is coming up all over a 2m x 3m bed. It is reaching over 2m tall is very upright, has pairs of leaves alternately up the stem that look hydrangea shaped, the tops are hairy and purple and the emerging pair of leaves have purple hairy backs. It has the remains of last year's small group of flowers at the tips of the old growth. Do I need to worry about this monster?