Likely as not, if you can lift it up, you can break it with the back hoe. You could manage OK with a 12" but just have to dig further out so the root isn't as big. I like my 7" because it is much easier to cut thru a root with the smaller bucket and then use the narrow width to get in between stabilizing roots and tap root to remove more of the dirt. I can dig them out with the 12", but it takes longer than using the 7". The 7" is custom made by cutting down an 18" by original owner. I think he found quickly that the 18" was too big for the little
B26. My super hard ground with lots of rocks is a chore on the 12" digging with it. Your soil may be much softer, if its any harder if would be a replacement for concrete.