we bought a house that has a tiny garden (2' x 10') that i need help with. this garden is wedged between my house & my front walkway & gets the full brunt of the afternoon sun until it sets. the soil is not the best & it's not very deep....maybe a foot. under the soil is broken up concrete from whatever was there before. i need a perennial that i can grow there that will tolerate the heat & the shallow soil. whatever finally decides to grow there can't be anymore than 2' high. what can i plant???