Attempting to pass props through render in Vue.js and watch them

I'm having trouble passing a prop from a parent down through a created child using CreateElement/render in vue.js and then watching it.

Here is my parent component

Vue.component('my-drawing', MyDrawing)

new Vue({
  el: '#drawing',
  mounted() {
    Bus.$on('emitColorSelection', (emitString) => {
      console.log("inside socket.js/my-drawing and emitString is ", emitString);
      this.useColor = emitString;
      console.log('inside socket.js/my-drawing and this.useColor after set is ', this.useColor);
    })

  },
  data() {
    return {
      channel2: null,
      canvases: [],
      useColor: 'rgba(255, 0, 0, 1)'
    }
  },
  render(createElement) {
    return createElement(MyDrawing, {
      props: {
        useThisColor: this.useColor
      }
    })
  }
});

So you can see here is that I take the value of the emit for some bus and then I pass that to useColor. I would like to then pass this value to my render function as useThisColor.

Here then is the child.

<template>
  //my template stuff
</template>

<script>
//stuff
  watch: {
    useThisColor (n, o) {
      console.log("useThisColor watch, ", n, o) // n is the new value, o is the old value.
    }
  } 
//stuff continues

So this watch tag doesn't output. I've also tried putting the props in the template to no effect, as well as trying to output it on a Updated: tag. I've also attempted to set props in the parent using quotes. Nothing so far has worked and I am a little confused. If anyone has any ideas please let me know.