Ceanothus cordulatus
mountain whitethorn
Overview
Ceanothus cordulatus is a low, spreading evergreen shrub of western mountains, growing 2-5 feet (0.6-1.5 m) tall and often wider than tall, with rigid, intricately branched gray-white stems ending in sharp spine-tipped twigs. The small alternate leaves are oval to heart-based, 0.4-1 inch (10-25 mm) long, gray-green, with three main veins and a pale waxy bloom that reflects light. In late spring it carries dense rounded clusters of tiny white flowers 1-2 inches (2.5-5 cm) long that release a sweet fragrance. The flowers give way to small three-lobed seed capsules that dry and split to eject the seed. C. cordulatus grows on dry, rocky slopes and openings in conifer forest, generally between 3,000 and 10,000 feet (900-3,050 m), and fixes nitrogen through root nodules that enrich poor mountain soils. It resprouts and seeds heavily after fire, often forming dense thickets. The rigid spiny branches make it a barrier to foot traffic, and its short lifespan and flammable foliage limit its use near buildings.
Native Range
Ceanothus cordulatus is native to the mountains of the western United States and Baja California, including the Sierra Nevada, Cascades, and southern California ranges. It grows on dry rocky slopes and in openings of montane conifer forest.Suggested Uses
C. cordulatus is used in dry native and habitat plantings, slope stabilization, and wildlife gardens in mountain regions, where its spiny thickets shelter birds and its flowers feed pollinators. Its nitrogen-fixing roots improve poor soils on disturbed slopes. The sharp spines and flammable foliage make it unsuited to plantings near paths or buildings.How to Identify
Appearance
Size & Dimensions
Height2' - 5'
Width/Spread4' - 8'
Bloom Information
C. cordulatus flowers in late spring and early summer, roughly May through July depending on elevation. The dense white flower clusters open over two to three weeks and draw bees, butterflies, and other insects with nectar and scent. Dry three-lobed seed capsules follow and release seed by late summer.
Detailed Descriptions
Foliage Description
Gray-greenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight