On our back patio we have this triangle-shaped planter. There is a large and beautiful Liquid Amber tree in the center of the planter that we don't really want to move due to expense and because it provides shade and fall color. Any ideas as to how we could use this space? A vegetable garden design or a type of plant that would bring color and/or fragrance? We are located in Southern CA so it has to be fairly hardy. With the tree overhead, it doesn't get much sun. Thanks for any ideas!