"Franz Heymann" replied:

R. rugosa hybrids are truly beautiful roses. I think your friend
should erect a hedge of them, putting them about a foot from the
border on his/her side, and then just sit down to await developments.
Don't bother about a complementary plant. There won't be room for it.
Hint: My rugosa hybrids are real beauties, but at four years of age,
they have diameters of about 8 ft and heights of about 5 ft.
---
Thank you to everyone, especially Franz, for your suggestions and advice.
I still like the thoughts of R.rugosa hybrids, as does my friend.
They would certainly stop the newspaper boy dead in his tracks when
attempting to cross the lawn. My ex boss used 'Masquerade' roses to edge
his very extensive and immaculate front lawn and they looked wonderful when
they were all in full flower.

Bella