I would bet I am asked this question more than any other...What plant is it between the stones in the courtyard garden?
We used 2 groundcovers that are excellent creepers. Blue Mazus tends to be very dominant. The other is Creeping Jenny that is typically an annual but some of the plants return year after year. The varying colors offer nice contrast but like I said, the Mazus will typically take over the Creeping Jenny. I just added another 3 flats of Mazus to the area last night where winter kill took its toll.