It appears you are in CA? Buy a Sunset Western Garden Book (Home Depot, Lowe's, garden centers, online). Will give you a wealth of info about your garden zone (different from USDA zones) and ALL appropriate plants for your space. According to several certified arborist I know, never plant a tree larger than a 15 gallon size. They will be much hardier and healthier as time goes by. Prepare, prepare, prepare your soil. Know how much time you have to spend on maintenance and choose plants accordingly. Always allow plenty of room to grow. Make sure to locate plants with similar needs (e.g., water, fertilizer) together. Choose plants that combine to give you interest year-round. And like others say, it's a process. Have fun!
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