Hi, I've been working on my fixer-upper home and one of this summer's projects is getting rid of a huge (80' x 8' x 45' ) overgrown cherry laurel. From what I have researched this invasive plant is poisonous in many different ways and will keep coming back years after getting rid of it.

Well I want to put up a fence, plant edibles, grass and other growing things and I am worried that any remaining roots might make a come back into the garden, or contaminate the food.

Do I have anything to worry about? And if I do then how many feet of roots do I have to take out to not worry so much about this?