Eriogonum giganteum is a large native shrub endemic to California's Channel Islands, primarily Santa Catalina and San Clemente Islands. It produces broad, flat-topped clusters of tiny creamy white flowers on stems that can reach 8 feet, set against silvery-woolly gray-green leaves. In the garden it serves as a structural focal point and one of the most dramatic California native shrubs available for low-water landscapes.
It thrives in full sun with excellent drainage and very little supplemental water once established. Overwatering or poorly drained clay soils cause rapid root rot and decline. Planting on slopes, in raised beds, or in sandy or gravelly soils mimics its native coastal sage scrub and chaparral habitat. A layer of coarse gravel mulch around the base helps keep the crown dry. Established plants tolerate summer drought and salt-laden coastal winds without stress.
The long-blooming flower clusters attract an exceptional diversity of native bees, butterflies, and beneficial wasps throughout summer and fall, making E. giganteum a keystone nectar source in California native planting schemes. Seeds are taken by native birds and small mammals after the clusters dry.
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.
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.