Noninvasive shade trees provide more than beauty and comfort in Northern California -- they also host local wildlife, help prevent erosion, resist degrading the water supply and are more resistant to fire than invasive specimens. Plant a noninvasive shade tree that meets your environmental and aesthetic requirements to contribute to a well-balanced ecosystem.
Native trees such as coast live oak, redwood and California buckeye are safe-to-plant shade-providers. Find specimens at California Native Plant Society sales, or speak to your local nursery about acquiring them. Remember that some native trees grow far too big for planting at home; consult a master gardener if you have questions about whether a native tree will outgrow the space where you are considering planting it.
Some non-native shade trees are not yet known to cause environmental damage, as they do not currently have the ability to thrive in the wild. Tupelo is a fantastic shade-provider whose crooked branches and blue fruit make it an especially attractive autumn and winter specimen. Tulip trees create excellent shade and produce an abundance of blooms in the spring. The hybrid crepe myrtle, with its brilliant flowers and vivid fall foliage, is a good choice for a hot spot where you desire color. The bronze loquat, whose leaves emerge bronze then turn green, is easy to grow and care for. The burr oak tolerates poor conditions and displays deeply lobed green leaves and an abundance of acorns. You may also consider water gum, southern live oak, marina strawberry tree, bald cypress, Japanese blueberry tree, Japanese snowdrop and dawn redwood.
Some non-native shade trees once thought to be safe may be found to cause damage over time. The best way to stay current on which shade trees are noninvasive is to communicate with horticulturalists at your local cooperative extension and follow news from the California Invasive Plant Council.
Trees to Avoid
According to the California Invasive Plant Council, planting the following trees that are known to be invasive seriously degrades the Northern California environment. Avoid blue gum eucalyptus, Russian olive, Mexican fan palm, saltcedar, Chinese tallow tree, myoporum, scarlet wisteria and Brazilian peppertree. Additionally, the following trees can be problematic, although it is unknown whether they cause permanent damage: Canary Island date palm, California peppertree, edible fig, olive, acacia, mayten, single seed hawthorne and black locust.
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