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As a general rule, avoid planting under the canopy of oak trees. It is recommended that you remove non-native plants from under oaks but avoid disturbing the soil or drainage patterns in the process. If you need to plant something, choose species that require similar soil types and watering. Avoid azaleas and rhododendrons as they typically require more water than is appropriate for oaks and may transmit diseases such as Sudden Oak Death.
In general, healthy live oak trees are able to survive the dry seasons and extended droughts we experience in California. In most circumstances it is not necessary to water mature established live oak trees. Shallow watering can in fact cause additional problems. Over watering or improper watering of oak trees may promote the growth of bacteria that can damage the root hairs and the ability of the tree to absorb water from the soil. Deep watering of oaks may be appropriate in some circumstances, but it is advisable to consult a certified arborist regarding watering of oak trees especially mature trees.
