My property relies on a stand of eucalyptus trees as a windbreak to protect the house from the cold winter southerly winds. The ground between the eucalypts and the house is otherwise well placed for a zone 1 vegetable garden. I need an effective biological root barrier, if such a thing exists, to exclude the eucalyptus tree roots from this vegetable garden area. I have thought of prostrate tagasaste, with their deep tap root, vetiver grass, also with the deep, dense roots, comfrey, also with the profuse deep roots. Any suggestions?