Before this season, I have never considered how my Shop vac could be used to make gardening easier. I had a long conversation with a friend and she said she does this every year! I asked people at a local Rose Society meeting and they looked at me like I was crazy! But I tried it and I do suggest it, with comments below.
First, consider the amount of loose soil is under your plant and if there would be a chance that much of it would get into and clog the vac.
Second, consider the amount of moisture currently in the garden. Leaves that are damp clog up the vac and tear the inner collection bag requiring replacement.
Third, consider the price of replacement bags. My model required me to go to Lowes for shop vac disposable bags at $15 for three bags.
If you choose to try this, one helpful hint is to position the vac suction hose in a linear way rather than coiled during use. It took me a few trials and jams to figure that out. Also, the tip of the suction end worked best by not hurrying and trying to get too much volume of leaves at one time.