I have a 4 foot poured concrete retaining wall in front of my house....?

so this wall began to crumble when i started removing huge overgrown bushes in front of the wall and the ones in my lawn at the top of the wall. I ume the roots did the job. So now the wall crumbles more each time it rains and i have a pile of concrete crumbles, rocks and dirt below each breech in the wall. I want to use plywood propped up against the wall and pour in new concrete to fill in the breeches. Will this work?