First, its a controlled waste so its an offence to take it to a regular tip. Tipping controlled waste other than at a licensed tip is a criminal offence.
Apart from that minor warning, its the devils own work to remove it. Just digging out the roots won't do it, you need to also dig out a meter all around the limits of the current growth.
Actually, it is legal to grow it in tubs because it spreads by its roots and not by blown seed.