Answer: What you can grow in your garden is limited only by the amount of sunshine it receives and what type of soil you have. If the soil is very heavy (clayey), you'll want to incorporate some organic matter as the first step in preparing the bed for planting. Organic matter such as compost, aged manure, peat moss, etc. will help the soil drain well and will supply nutrients to plant roots as it decomposes.
The east side of your house probably gets morning sun and afternoon shade. There are many flowering perennials that would be happy there and many annuals that you can plant to fill in bare spots. Decide first if you want a theme; a favorite color, a cutting garden, one that attracts wildlife, or perhaps a woodland garden effect. Since you're gardening in southern California, there are very few plants that you cannot grow! (Lucky you!) The Monrovia website has pictures of some theme gardens, along with diagrams and plant lists. That might be a good place for you to start. Even if you don't like everything in a particular theme garden, you can certainly choose the plants you do like and incorporate them into your new garden.
Most "shade" loving plants and all plants for "partial shade" will be happy in an east-facing garden, but you should avoid planting anything that requires "full sunshine". This equates to a minimum of 8 hours of direct sunlight each day and without adequate exposure to sun, these plants will be spindly, fail to flower, and susceptible to fungal diseases.
Be sure to visit the Monrovia website and visit the theme gardens - I know you'll come away with lots of great ideas!
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