The Island Oak (Quercus tomentella) is the rarest of all California tree oaks, growing natively only on the islands off southern California, and in northwestern Baja With its upright evergreen growth habit, strong branches, good pest and disease resistance, and good drought tolerance, Island Oak has proven to be a surprisingly solid performer in urban locations throughout California.

Over the span of geological time, Island Oak has grown throughout coastal California, and fossils of Island Oak can be found in the Bay Area, dating to 5 million years ago. Island Oak is an excellent climate change migration and adaptation native tree species for locations throughout coastal and even inland California, especially the Bay Area, and Island Oak particularly thrives along the Central Coast.

Island Oak really needs planting locations with deep, permeable soils, mimicking the soils of their island canyon homes. Island Oak will thrive anywhere the similarly deep soil favoring Valley Oak (Quercus lobata) grows well. But with its vastly greater resistance to powdery mildew, and better shade tolerance, Island Oak is well adapted to coastal and near coastal planting locations where Valley Oak struggles.

As a tree, Island Oak is typically a bit gawky when young, and fairly slow growing. Island Oak is particularly well-suited to use as visual screening, if the slowish growth habit can be tolerated. But with a bit of time, Island Oak is a fantastic, upright branched native tree that can diversify a native California planting palette in an interesting way.