I remember a post about trapping the stuff in a corner created by two plywood boards. It was several years ago, and I didn't find it. I generally have the opposite problem that stuff just ends up under the chipper which I have to remove or continually move the chipper. I think if I had your problem, I might try working very near to a couple trees and spread a large tarp extending from the ground under the chipper that extends to and then up into those trees so that the 'corner trap' is created. The best feature is it would allow you to move the mulch afterwards.

Go down to your local Tractor Supply or Harbor Freight and buy a small tarp. 4'X6'. Tie the corners of the 4 foot side and attach the resulting tube to the shredder out feed.

Problem solved for a couple of dollars. less if yo watch for a sale.

Alternately. Buy a much larger one, it support the two ends and make a big canvas basket to collect the shredded material. When done shredding pull the corners together and move the shreddings to where you want them It will make the clean up easy.

What a great idea! I tried it and it worked GREAT - just what I wanted. Thanks for answering my post! - Jim