The easiest plants to grow tend to be those that are naturally part of the area. Also planting native plants will help conservation efforts and keep natives from becoming endangered or threatened. Native plants of California are best suited for the growing styles of that particular area and should be incorporated in those gardens whenever possible.
Sugar Bush, Rhus ovata, is an evergreen. It will get between 8 and 12 feet tall. Flowers are from March to May, blooming white. Growing conditions will need to have full sun and no excess water in soil between 8 and 8 on the pH scale. It has edible fruits and will attract birds. Grow in USDA hardiness zones of 6 to 10.
Heart Leaved Penstemon
Heart Leaved Penstemon, Keckiella cordifolia, is an evergreen in warm climates and deciduous in cool climates. It will get 3 to 6 feet tall with tubular red flowers 1 to 2 inches long. Flowers appear May to July. Foliage is dark green and glossy. Growing conditions need to be sun or partial shade with soil pH of 6 to 8. It will attract hummingbirds to the landscape. Grow in USDA hardiness zones of 6 to 10.
Owl's Clover, Orthocarpus exserta, is an annual. It gets to 1 ½ feet tall. It has pinkish purple flowers that appear in spring and are very showy against the green background. Grow in any soil in a soil that has a pH range of 5 to 8. Grow in USDA hardiness zones of 8 to 10.
Arizona Ash, Fraxinus velutina, is a deciduous tree. It will get 30 to 50 feet tall. Leaves are glossy green and velvety turning gold in the fall. Growing conditions should be well drained soil with a pH of 6 to 8 in full sun. Propagate via seed and grow in USDA hardiness zones of 6 to 10.
Joshua Tree, Yucca brevifolia, is a tree that gets up to 20 feet tall. It is a slow grower and it has many different forms. Dark green leaves are like bayonets like many of the Yucca standards. Growing conditions should be well drained and sunny with a soil pH of 6 to 8. It can tolerant sandy locations. Grow in USDA hardiness zones of 6 to 10.