grow together
(of things) To physically move closer together and connect or intertwine over time. That big bush out front is actually two smaller bushes that grew together. Molly, you have to wear a cast so that your broken bone grows together.
grow together
[for things] to join together as they grow and develop. Two of these trees grew together when they were much smaller. The broken ends of the bone grew together far more rapidly than Chuck had thought.