I'm back with another of my dog-walk inspired questions. This plant appears everywhere on my walks with my dog. It's a low-lying ground cover with viney stems and small white cup-like flowers. It would be perfect for a narrow area between my house and a brick walk way, but I don't know if it's a perennial or an annual. (I suspect it's a self-seeding annual, based on where it comes up.) I'm sure it's considered a weed where I see it (along curbs and in thinly mulched flowerbeds), but I like it and would consider it suitable for the purpose of filling in a six-inch area between the house and the walk (just there to allow drainage from the walk).