Invades along the coast from Sonoma County to San Diego. Forms dense stands with no other vegetation. Can cover large areas. Spread by birds. Leaves and fruits are toxic to wildlife and livestock. Burns easily. Doesn't typically spread in interior areas.
Brazilian pepper, California pepper or Peruvian pepper
Schinus terebinthifolius or Schinus molle
Pepper trees are native to South America (despite the fact that Peruvian peppertree is sometimes called California peppertree). Seeds are transported by birds and mammals into natural areas. The aggressive growth of peppers enables them to displace native trees and form dense thickets in natural areas. They produce undesirable suckering and sprout unwanted seedlings. A serious problem in southern California. Less of a problem in the San Francisco Bay Area and Central Valley, but care should be taken if planting near wildlands.
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.
An established invader of the Pacific Northwest, now spreading through northern California. Capable of long-range dispersal by birds. Creates dense thickets, changing the structure of woodland understories. May hybridize with and threaten native hawthorn species.
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.
Blooms like clouds of the whitest, feathery flowers. Handsome bark provides winter interest. Will grow in most central California environments. The olive-like fruits can be a litter problem. May produce a significant amount of pollen. Deciduous. Zones: 3-9, 14-24. Height: To 20 ft., not quite as wide.
Fast-growing and easily trained. New leaves emerge bright copper before turning green. Bunches of creamy white flowers in spring. Easy to plant and care for. Requires well-drained soil. Can be subject to fireblight. Evergreen. Zones: 8-24. Height: 12-30 ft. Width: 15-30 ft.
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.
Slender, graceful trunk. Broad crown. Leaves may turn red or yellow in fall. Delicate, fragrant, white flowers hang below leaves, creating a layered effect. Deciduous. Zones: 4-9, 14-21. Height: 30 ft., narrow in youth, wide in maturity.
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.
Formal plant; can be trained as a single or multistemmed tree. Mahogany-colored bark peels, revealing new, satiny white bark beneath. Yellow flowers produce a good show. Can be slow-growing. Damaged by very cold winters. Try cultivar 'Elegant'. Evergreen. Zones: 15-24. Height: To 45 ft. Width: 5-30 ft.
One of the cleanest, most graceful eucalyptus, with weeping branches and not too much litter. Crushed leaves smell a bit like peppermint. Furrowed, rich, reddish-brown bark. Damaged by very cold winters. Evergreen. Zones: 5, 6, 8-24. Height: 36-48 ft. Width: 15-36 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.
Delicate, feathery foliage sprays turn reddish-brown before dropping in the fall. Tolerates drought or very wet conditions, and any but the most alkaline soil. Trunk can be buttressed at the base. No pests or diseases. Easy to plant and care for. Tolerates any amount of water. Deciduous. Zones: 2-10, 12-24. Height: 50-70 ft. Width: 20-30 ft.
Rugged-looking tree with flaky grayish bark. Long, deeply-lobed leaves are glossy green. Large, distinctive acorns covered in fringed cap. Tolerant of poor conditions. Acorns can be a trip hazard. Deciduous. Zones: 1-11, 14-23. Height: 60-75 ft., equally wide when mature.
Straight, columnar trunk with a tall, pyramidal crown. Unique lyre-shaped leaves. Foliage starts bright green, turns bright yellow in fall. Tulip-shaped flowers in late spring are interesting but not showy. Beautiful large shade or lawn tree. Likes slightly acidic, well-drained soil and plenty of room. Deciduous. Zones: 2-12, 14-24. Height: 60-80 ft. Width: To 40 ft.
Soft, pale green needles turn reddish-brown before falling in autumn, leaving a beautiful winter silhouette. Grows very fast when young. Older trees have fluted trunks. Resistant to oak root fungus. Not suitable for very arid regions or the coast. Deciduous. Zones: 3-10, 14-24. Height: To 90 ft. Width: To 20 ft.
New leaves rusty and hairy, turning smooth and bright green. Old leaves turn red before dropping. Blooms with tiny, scented, white flowers in clusters followed by small, blue-black, edible fruits. Likes rich, well-drained soil. Needs little pruning. Evergreen. Zones: 8-9, 14-24. Height: 30-60 ft. Width: 20-30 ft.