Prunus ilicifolia ssp. ilicifolia is an evergreen shrub or small tree native to California's coastal ranges, chaparral, and foothill woodlands, ranging from Napa County south through Baja California. Its thick, spiny-toothed leaves closely resemble English holly through convergent evolution, providing dense, glossy, year-round structure. Small white flowers appear in spring racemes, followed by cherries that ripen to deep red-purple by late summer.
Established plants are highly drought-tolerant and perform best with little or no summer irrigation; summer water promotes Phytophthora root rot and crown disease. The species tolerates poor, rocky, or clay soils as long as drainage is adequate and prefers a pH of 6.0–7.5. It resprouts vigorously from the base after fire and is a foundational species in chaparral and coastal scrub plantings. It can be maintained as a dense screen or informal hedge, or left to develop as a multi-stemmed specimen. Susceptible to Phytophthora ramorum, the pathogen behind sudden oak death, and should not be planted near known infection sites.
The thin fruit pulp is sweet and was eaten fresh by Chumash, Ohlone, and other California Native peoples. The large seed kernel, known as islay, was leached in running water or roasted to reduce cyanogenic compounds, then ground into meal for porridge or flatbread. Ripe fruit is a high-priority food source for birds, coyotes, and other wildlife.
Shot Hole Disease
Small reddish-purple spots on leaves that dry out and drop, leaving ragged holes across the leaf surface. Severe infections cause early defoliation. Dark sunken lesions may appear on young stems.
Remove and dispose of infected leaves and stems. Avoid overhead irrigation and wetting foliage. Apply a copper-based fungicide in fall just before seasonal rains begin; repeat in early spring if the previous season was severe. Ensure good air circulation through selective pruning.
Powdery mildew
White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.
Armillaria Root Rot
Thinning, yellowing canopy with progressive dieback; white, fan-shaped mycelial mats visible beneath bark at or just below the soil line; honey-colored mushroom clusters appearing at the trunk base or on surface roots in autumn.
No chemical cure exists. Improve drainage and avoid any injury to roots or trunk. Remove severely infected trees along with as much root material as possible. Do not replant susceptible species in the same spot.
Phytophthora Root Rot
Wilting despite moist soil, yellowing leaves, stunted growth, and dark, decayed roots and crown tissue. Vines may collapse during hot weather.
Plant in well-draining soil and avoid waterlogging. Remove and destroy affected vines. Improve drainage with raised beds or amended soil and avoid overwatering.
Sudden Oak Death
Reddish-brown to black bleeding cankers on the lower trunk ooze dark sap; inner bark beneath the canker is stained deep red-brown. Foliage may wilt and die rapidly as the canker girdles the stem. Leaf lesions occur on some hosts but are secondary on oaks.
No systemic cure is available once infection is established. Preventive trunk injections with potassium phosphite applied before infection can slow canker progression in high-risk areas. Remove and chip or burn infected wood on-site; do not transport infected material off the property. Report confirmed or suspected cases to the California Department of Food and Agriculture.