You sound as if you were frantic. If it is growing
quickly, then it is already way beyond stopping.
But don't let that discourage you. The best relationships are the ones worth working on to your best effort. Your best bet is to dig up every plant
that you do not want all the way to root tip. Some things will reproduce from a sliver of root.
In the future, try pre-emergents; unless you are planting from seed
. if you are totally organic, you can still find help. Research how to control your garden; take a class; talk to the guys at the local nursery until they know your name. The local extension agent can also be valuable.