Ask Mr. Smarty Plants

Cotoneaster dammeri is certainly a popular groundcover plant in many parts of the country. It is native to Central and southern china and consequently is not in our plant database.  But this Mr. Smarty Plants has experience with this plant and that combined with an internet search has revealed information about the bearberry cotoneaster that may be helpful to answer your question.  Cotoneaster dammeri is a fast-growing, low, evergreen shrub with creeping branches. The foliage is glossy, dark green during the summer and turns purple-red in the fall. Small white flowers in early summer are followed by bright red fruit in the fall and winter. It is happy in full sun and will tolerate semi-shade. Given time, it will form a dense matt of branches, completely covering the area. There are many cultivars of Cotoneaster dammeri with differing heights and fruit color.

Your other suggestion is also not a North American native plant and consequently it is not in our plant database.  Sarcococca hookeriana  (sweet box) is native to China and grows best in organic, rich, acidic, well-drained soils in part to full shade sites. The leaves bleach out in the full sun. It grows slowly and is best grown with consistent moisture. Established plants have some drought tolerance. It is a tall shrub to 5 feet tall and will spread to about 6 feet wide over time. It is a tall groundcover and will produce a very different effect to the cotoneaster.  For a lower growing groundcover make sure you plant Sarcococca hookeriana var. humilis if you are going to use this. This natural selection only grows to 1-2 feet tall. The Missouri Botanical Gardens Plant Finder is a good place to find detailed information about this plant.

Another place to go to find a list of potential groundcover plants is our Native Plant Database.  Use the Combination Search feature instead of Recommended Species. This will provide a bigger selection with much more choice to narrow down. The volunteers and staff at the Wildflower Center who maintain the database have partners in different regions to help with these recommended species lists based on what is easy to access in local nurseries.
Under Combination Search, select the following categories: CA, Habit – Shrub, Duration – Perennial, Light Requirement – Sun & Part Shade, Soil Moisture – Dry, and Size – 0-3 feet.

Some native plants to consider are:

Arctostaphylos uva-ursi (kinnikinnick) A trailing, evergreen shrub with thick, leathery leaves that are yellow-green in the spring, dark green in summer and reddish-purple in fall. Nodding clusters of pink or white flowers are followed by bright red berries that persist into winter. A hardy shrub for  dry, sunny sites.

Gaultheria shallon (salal)  To 3 feet tall, with spreading branches that root when they lay on the soil. Large, leathery, evergreen leaves are dull green and become reddish in winter. Whitish to pink glowers followed by dark blue berries. This plant must have summer fog or rain and shade. Direct summer sun causes scorch. This easy ground cover can become somewhat invasive. 3862

Mahonia repens (creeping barberry) A stoloniferous, sprawling evergreen growing to 3 feet with fragrant, showy yellow flowers followed by purple fruit. Leathery, holly-like, muted green foliage turns mauve in winter. Best in part shade and away from drying winds.