Hello, echar raíces = (figurative) put down roots En el caso de tu pregunta, necesitamos saber algo más del contexto. Yo la interpreto como un reproche. Algo así como: !Llevas tanto tiempo en ese sitio sin moverte que te van a salir raíces! Un saludo.

Establecerse o asentarse [alguien] en un lugar de forma fija y duradera. :)

wee need a context, this is commonly used when there is someone lets sey a single guy that has no a serius relationship, has no a formal job, then is compared with a bird, cause he "moves easily" but if this guy grew up, he settle dawn "hecha raices" then he has now a formal job a girlfriend that is possible to get married with "formal relation" or even a whole family, then you can't "move easily" so you are more like a tree, my opinión of course