Cotoneaster horizontalis Decne. var. perpusillus
Rock cotoneaster is native to western China, but has escaped and is now found in some areas of North America.
Identification: These plants are prostrate, spreading horizontally over rock surfaces. They are 12-30" (30-76 cm) in height—the ones I have seen so far are plastered nearly flat against the rock. They may spread up to 8' (2.4 m). Stems may have a fishbone pattern. Leaves are alternate, unlobed, dark green on top, light green and finely hairy below, ⅛-¼" (6-8 mm) in length. Plants are semi-evergreen, retaining at least some leaves in winter; leaves become tinged with purple. Flowers are pale pink, appear from May to June. Berries are bright red, oval-shaped, ~³/₁₆" (5-6 mm) × ¹/₁₆-⅛" (3-4 mm), distributed evenly among the foliage.
Cotoneaster horizontalis var. perpusillus at the University of Connecticut Plant Database
Cotoneaster horizontalis var. perpusillus at the Missouri Botanical Garden
Cotoneaster horizontalis var. perpusillus on SEINet—the Southwest Environmental Information Network
Cotoneaster horizontalis var. perpusillus on eFloras
Cotoneaster horizontalis var. perpusillus description by Thomas H. Kent, last updated 25 May 2020.
Range: Zones 5a-7a: