It's a forever kind of battle, especially if it gets good watering on the rental side. don't know how you feel about roundup but even then you will have to reapply every now and then.

A physical barrier sounds like the way to go. If you try to poison the Vinca you will spend the rest of your time at your place poisoning it.

I would contact the owner of the house with a registered letter requesting that he/she prevent the encroachment, and if nothing is done, sue in small claims for continuing nuisance.

Ordinarily in small claims one cannot sue for anything except money, so I would get several bids on the cost for labor and materials of a permanent mechanical barrier such as a stone wall.

In fact, there are suits for such, running bamboo is a popular subject, and I'm sure spaces where the ground takes a great deal of care and expense, like a golf course, or an ornamental pond, would insist that neighbors control invasive plants.

I agree with tete on the physical barrier, such as deep edging in the ground combined with an above-ground edge, such as brick. If you poison the plant with Roundup and it affects the neighbor's vinca, you run the risk of a lawsuit.

gardengal - how deep would you recommend for the barrier. I'm having the identical problem along my fence. I found something at Walmart, not too expensive (I have a long run of fence - gotta go as cheap as possible), which is probably about 4 inches. Do you think that will discourage the vinca?

Yes, vinca is a surface rooter, which is one of the reasons it is easy to pull up when it starts growing where not wanted.

Thanks... I'll give it a try. The vinca may be easy to pull up, but its creeping in behind trees, shrubs and other plants that will only get bigger in time - making it harder to reach and control. So if I can stop it now that would be best.