Crayons can be used to create colour on fabric by direct or tranfer technique
You can see the transfer is not good. The crayons have less pigment and they simply soak into the paper when you iron it.
One technique that works well with these crayons uses parchment or baking paper
Pull the two pieces of parchment apart when cool. If you pull them apart when hot, you will have gray on on both pieces
Place the parchment crayon side down and iron onto the fabric. This speckled texture is useful for rocks or pebbles.
This second scribbled parchment is done with fabric crayons
As you can see the transfer is much better
You can also transfer to scrunched fabric (FabricCrayons)
This is the result
and when un scrunched. It is certainly a candidate for layers
Here I am layering a scribbled (Fabric marker) over it
Thr result is that the first layer is a bit over powered. However, the scrunching technique is great for overlays on pale coloured fabric or with metallics.
Using the flaking method you can add layers until you like what you have
then some branches.
Draw directly on the fabric