Description

This walnut grows throughout much of the state, but is more common from the SF Bay Area north to Redding. It is thought to have been introduced to many sites by indigenous peoples who utilized the wood and fruit. Early orchardists used it as rootstock for the English black walnut, Juglans regia. One often discovers our native black walnut in old orchards where the rootstock has overwhelmed the long-departed graft. This is a large, round tree with frond-like compound leaves held over furrowed (when mature) gray bark. The clusters of creamy white flowers yield round walnuts with edible fruit. Although drought tolerant with age, the black walnut does well with supplemental irrigation. This tree is known to be rather allelopathic, meaning it will suppress the growth of other (by no means all) plants within its dripline and beyond. If you are fortunate to have a mature black walnut in your garden, research and some trial and error will yield some tolerant companions.