I figure, wrap an asteroid with plastic, pump in some air, and plant kudzu.
Come back in a day or two and introduce some goats.
Come back in a year or two and harvest meat, dairy products, cheese, and so forth in endless quantities.
Outer space will need places where food can be grown, and the aggressive plants of Earth may get to enjoy being ostracised.
Sounds like a perfect solution. I think Kudzu is the greenest thing on earth.