I've done it many, many times. I use a self propelled grinder, it cuts a great 3" width trench, the problem is it throws the dirt right back in - so make a deflector on your back flap and throw the dirt to one side.
The other downside is you can only cut about 8" deep with a small self propelled, otherwise the head drive gets in the way.
If you swing the head to one side your trench will get wider.
I find the stumpcutter does a great job, doesn't bounce on the roots like a trencher, it goes right through them.
I've also tilled many a garden - again does a great job.
You might throttle down a little from the full throttle you normally cut with.
Good luck!!