Lily of the valley - invading from the other side of the fence
Dear fellow-gardeners, please share your experience with a gardening novice.
In our newly acquired garden in spring there was a small patch of lilies of the valley. I didn't think much of it, in fact I found them pretty.
However when I tired to plant some other plants in this area I was shocked when I saw that there are dozens of the roots with the white buds on them, all just waiting to come out. What makes the situation worse they all are coming from neighbours garden. Normally I would just keep weeding them out until they are all gone, but in this case it won't help as they'll just keep coming from under the fence. Nobody is living in the house, and I think it might be for sale or similar, so I can't really go and talk to the neighbours about it.
I started looking for some kind of a barrier to dig in along the fence but frankly was a bit lost.
Did anybody have a similar problem before? How deep do they grow and would a barrier actually help?
I don't have a lot of space in my garden and the roots of those lilies of the valley occupied the best spot, so I don't feel like I can't plant any actual plants there until I got rid of them.