Questions

I have a large concrete back yard with swings etc, surrounded by mass concrete walls, 1m up to 2m in height with a beech/whitethrorn hedge on top bordering field. Can't plant in concrete unless pots?? Looking for a creeper that will grow down and not effect hedge on top, would ivy strangle it as it will need to be planted at base of hedge, need colour to break up grey look, kid friendly. Advice needed