The banana plants have been there for many years, unknown how long, we only brought the house 6 months ago. The soil from the back garden (where the trees were) was dug up with an excavator and moved to the front garden, so thinking maybe some roots were accidentally picked up by the excavator? The front garden is new, used to be a sunken driveway but now is a garden after the addition of a retaining wall, and we filled in the hole with the soil from the back

Will try breaking them off as they come up, fingers crossed this is all that is needed! Thanks for the advice :)

If you have an old knife with a long blade use that to cut off the shoots as deep as possible. It'll be a lot easier that way with least disturbance to the soil surface.

Undiluted Round up on the stump of the shoot works well. It was how we killed ours accidentally.

I had the same thing happen not long ago when I took out a banana that had evidently been there for some time. I discovered an old, rotting corm next to it, which must have been the original banana plant from years back. Although it was rotting, it was sending out shoots. Then even more came up, and I eventually had to dig out a 5' x 5' area to find and destroy all the old corms, which eviidently just lurk until they want to really annoy you. If you don't get all the corms, they'll just keep coming up. Cutting off the shoots will only encourage them to make more shoots.

I had the identical aspect show up no longer lengthy in the past once I took out a banana that had clearly been there for a while. I found a vintage, rotting corm next to it, which ought to have been the unique banana plant from years again. Although it was rotting, it becomes sending out shoots.

I had a similar/worse problem with a neighbor's bamboo. In order to get rid of it, I had to dig up all the bamboo and the perimeter, lay down one of those black garden mats, put down a layer of small rocks, then add back the soil. That included going into the neighbor's yard and digging up his bamboo and doing the same thing over there. Of course he denied that he planted the bamboo but since it was a rental, I had to get it out because it can damage the foundation of a house.

I also had another renter that planted a tree within 15 feet of the house. By the time I realized that he had done that, it had already traversed under the foundation. I was told to leave it alone. This renter had 1/3 of an acre to plant it but since he was lazy, I guess he didn't want to walk far to

water it.