Cotoneaster horizontalis or Rock Cotoneaster is a deciduous shrub, native to the cooler moist climate regions of Asia. In warmer and drier western gardens they benefit from partial shade, richer soils and more frequent watering. However, they are tough and adaptable and once established they require little care. This shrub is most successful when planted where minimum winter temperature range from -30° to 10° F (Zones 4-7).
The Rock Cotoneaster is a low spreading shrub with semi-evergreen foliage, growing 2-3 feet hish, spreading up to 12-15 feet wide. The arching branches have 1 / 2 inch wide, round, glossy, deep green leaves that grow in a distinctive herringbone pattern. The shrub has almost undetectable small pale pink flowers that bloom mid-summer. Leaves turn red with cooler weather and colorful red fruit develops in winter. The flower nectar encourages visits by hummingbirds and butterflies and the fruit is edible for birds and squirrels.
This variety of cotoneaster is well suited for the Las Cruces area when planted with some protection from intense heat and sun. It is a popular bank cover and rock garden plant. The shrub has a carefree appearance due to the branch growth and should not be sheared. Instead, the branches should be selectively pruned to maintain the desired shape. It is a good plant for adding shape and color contrast along a walkway or around trees.
-Cheryl James Agro / Hort 100, Spring 1999