Blue Peter gardener Chris Collins celebrates the humble and sometimes hated plants we call weeds. He discovers that there is no such thing as a weed, botanically speaking, and that in fact what we call a weed has changed again and again over the last three hundred years. Chris uncovers the story of our changing relationship with weeds - in reality, the story of the battle between wilderness and civilisation. He finds out how weeds have been seen as beautiful and useful in the past, and sees how their secrets are being unlocked today in order to transform our crops. Finally, Chris asks whether, in our quest to eliminate Japanese Knotweed or Rhododendron Ponticum, we are really engaged in an arms race we can never win. We remove weeds from our fields and gardens at our peril.