Although not commonly sold in nurseries, this tree is sometimes "shared" among gardeners. Tree-of-heaven produces abundant root sprouts that create dense thickets and displace native vegetation. These root sprouts can be produced as far as 50 feet away from the parent tree. In California, it is most abundant along the coast and Sierra foothills, as well as along streams. A single tree can produce up to a million seeds per year.
Found along the coast from Humboldt to San Diego and in the Central Valley. Most invasive in coastal locations. Easily invades native plant communities, causing declines in native plant and animal populations. Fire departments throughout Southern California recommend against using eucalyptus trees for landscaping because they are extremely flammable.
Found throughout California. Able to spread long distances with the help of birds and mammals. Invades river and stream corridors, pushing out native willows and cottonwoods. Reduces water levels. Provides poor wildlife habitat. Serious invader in other western states.
A serious invader throughout California and southwestern states. Uses excessive amounts of water, increases soil salinity, changes water courses. Diminishes wildlife habitat, and increases fire hazard. Not commonly sold but still occasionally available.
Chinese talow trees are able to produce a large number of seeds and new shoots can sprout from roots. Seeds are dispersed by birds and in moving water, where they can remain viable for several weeks while floating. Wetlands, creeks, rivers, and native plant habitat are particularly vulnerable to infestation by this tree. A huge problem in southern states, this species has recently been found in California wildlands. Grows and spreads rapidly, pushing out native plants.
Can be a problem in the San Francisco Bay area, the Central Valley, and southern California. May be spread by birds and deer, as well as by vegetation fragments. Can dominate stream and riverside habitat.
Stunning tree; great in a hot area. Showy summer flowers in hot pink, white, lavender, and other colors typically give way to brilliant fall foliage. Somewhat susceptible to aphids. Not the best choice for coastal locations. Deciduous. Zones: Varies by hybrid. Height: 8-25 ft., varies by hybrid.
Can be fast-growing. Rosy pink flowers bloom before new leaves appear and are followed by beanlike pods. Prefers well-drained soil. Cercis reniformis 'Oklahoma' is also popular. Deciduous. Zones: 1-24. Height: 25-35 ft. Width: 25-35 ft.
Rosy pink, urn-shaped flowers, deep red bark, and strawberry-like fruits in yellow and red. Easy to plant and care for. Can be susceptible to greenhouse thrips. Doesn't tolerate very alkaline or poorly-drained soil. Can be slow to reach tree size. Evergreen. Zones: 8,9, 14-24. Height and Width: To 40 ft.
Crooked branches and dark, red-tinged bark make a dramatic winter picture. Birds are attracted to the fruit. Leaves turn yellow, orange, and red before dropping in fall. Excellent shade tree. Poor in air pollution. Needs acidic soil with no salinity. Deciduous. Zones: 2-10, 14-21. Height: 30-50 ft. Width: 15-25 ft.
Evergreen tree 20 to 60 feet tall. Makes an excellent street tree or individual specimen in a park setting. One of the most pest-free trees, able to tolerate a variety of soil conditions and temperatures. Can also be used as a hedge or screen plant. Many species and varieties are available at nurseries.