Take it off

Take it all off

Here is a link that might be useful: B&B rootball pdf

I agree. First, not all burlap is easily biodegradable - a lot has been treated to resist decay to lengthen its usefulness in a nursery setting. And even untreated burlap can break down slowly, interferring with natural root growth.

The burlap is there for the convenience of the nursery grower, not for the health of the plant. Get rid of it.