Quercus × ewanii
Ewan's oak
Overview
Quercus x ewanii is a hybrid scrub oak native to southern California, formed where the ranges of related shrubby and tree oaks overlap. It grows as a dense, evergreen large shrub to small tree 6–15 feet (1.8–4.5 m) tall, with a broad, twiggy crown. The leathery leaves are 0.8–1.5 inches (2–4 cm) long, oval to oblong, dull to grey-green, and edged with spine-tipped teeth, holding on the plant through the year. New leaves emerge in spring and older leaves drop gradually rather than all at once. Small yellow-green catkins of male flowers hang in spring, with inconspicuous female flowers on the same plant, followed by acorns that ripen in a single season. The acorns are intermediate in size and cup shape between those of its parent oaks. It grows on dry, rocky, well-drained slopes in full sun and tolerates heat, drought, and poor soil once established. Growth is slow, and the shrub tolerates neither regular summer irrigation nor wet soil, which can bring on root disease.
Native Range
The hybrid occurs in southern California, in the chaparral and foothill woodland of the Transverse and Peninsular Ranges, where its parent oaks grow together. It is found on dry, rocky slopes and ridges.Suggested Uses
Planted in native, chaparral, and water-wise gardens of the Southwest, and on dry banks for erosion control and wildlife cover. The acorns and dense growth give food and shelter to birds and small mammals.How to Identify
Appearance
Size & Dimensions
Height6' - 15'
Width/Spread6' - 12'
Bloom Information
Yellow-green male catkins hang from the branches in spring, usually March to April, shedding wind-borne pollen. The small female flowers on the same plant are easy to overlook. Acorns develop over summer and ripen the same autumn.
Detailed Descriptions
Flower Description
Yellow-green (catkins)Foliage Description
Grey-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
Care & Maintenance
Care Guide
Grows in full sun on dry, rocky, sharply drained soil with a pH from 6.0 to 7.5 and needs no summer water once established. Summer irrigation on heavy soil encourages root disease, the main cause of decline. Young plants grow slowly and develop a deep root system before much top growth. It tolerates heat, drought, and wind on exposed slopes. Established plants resprout from the base after fire or hard cutting. Hardy through about USDA zones 8–10.Pruning
Little pruning is needed beyond removing dead or crossing branches in winter. The shrub resprouts from the base, so it can be cut hard to renew an old plant. Pruning is kept to the dry season to limit disease entry.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
winter