One of those metal leaf rakes might work. You may even have one. Some are wide, some narrower. I know you want to get the needles and not the granite. The one I'm thinking of is called Flexrake on Amazon, a very common rake.

Rake.

This is exactly why I won't have decomposed granite again. There are other issues, but that's a huge one.

We got rid of the tree.....

try a leaf vacuum (most blowers can be used as a vacuum with a bag to capture the leaves). The vacuum will not have the force to pick up much of the DG and any that does will just fall back out of it when you power it off. I have been using this to keep gravel and DG areas clean in my own yard.