Patio with very large thick flagstones abutting a large slightly "industrial" looking but whitewashed wall of a veranda. I want to look into the possibility of drilling a hole in one of the flagstones to plant a [very] hardy climber preferably with attractive flowers to grow up the wall. As mentioned the wall is sun facing and gets a lot of relentless sun during the summer. I don't know what exactly is under the flagstones although it will be a mixture of soil and maybe some builders debris (bricks stones etc) from when the patio was constructed. Am totally totally clueless about climbers, which are hardy, whether it is infact possible to do this and if it is will anything survive, how much watering would be required until the plant is established. The patio is set within mature gardens where there are lot of trees and flowers growing so the general soil of the garden is not bad. location of the garden in question is huddersfield. Any thoughts?