It's Lamium galeobdolon 'Variegatum' (common name dead nettle or silver nettle). It's extremely fast growing and invasive. It's fine in a container but I would not plant in the garden unless you don't mind it spreading everywhere! It's like mint in the way it grows and runs in the garden. I hope this helps!

I found a similar bench at following site http://www.inewidea.com/2011/06/27/38868.html#more-38868
It's a Cricket Forge Leaf Bench and Table set for $2370