Tree-of-Heaven:  Ailanthus altissima. Originally from China; rapid growing tree to 80 feet tall; alternate, compound leaves, 10-40 leaflets with smooth margins on 1- to 3-foot stalks. Large terminal clusters of small yellowish-green flowers yield wing-shaped fruit on female trees. Forms thickets and dense stands.  

Chinese Tallow:  Triadica sebifera. Introduced from China in the 1700s as an ornamental and for its waxy seeds. Deciduous tree reaching 60 feet in height. Readily invades open land and has distinct heart-shaped, alternate leaves that display brilliant fall colors. Attractive white berries persist on the tree in the fall and winter.

Chinese Privet, Glossy (Japanese) Privet: Ligustrum sinense (and others). Native to China and Europe and brought to the U.S. by the mid-1800s as ornamentals. Mostly evergreen, thicket-forming shrub having opposite, elliptical leaves with smooth margins. Fragrant, white flowers form in spring and produce clusters of dark purple berries.

Paper mulberry:  Broussonetia papyrifera. Native to Asia. Paper mulberry was introduced for use as a fast-growing, ornamental shade tree. In its native lands, paper mulberry is used in paper making. In Hawaii and other parts of the South Pacific, its bark is used to make cloth. In the United States it is found from Illinois to Massachusetts, south to Florida and west to Texas. Paper mulberry is an invader of open habitats such as forest and field edges.

Salt cedar:  Tamarix spp. Salt cedars are characterized by slender branches and gray-green foliage. The bark of young branches is smooth and reddish-brown. As the plants age, the bark becomes brownish-purple, ridged and furrowed. Leaves are scale-like, about 1/16-inch-long and overlap each other along the stem. They are often encrusted with salt secretions. From March to September, large numbers of pink to white flowers appear in dense masses on 2-inch long spikes at branch tips.

Chinaberry Tree:  Melia azedarach. Introduced from Asia in the mid-1800s as an ornamental tree. Dark green leaves are doubly compound, alternate, deciduous, and display bright yellow fall colors. Fruit is spherical, about ½" in diameter, yellow, persists on the tree in winter and is poisonous.  

Chinese Pistache:  pistacia chinensis. Growing to 25 ft (8 m) in gardens, this deciduous species has glossy green leaves consisting of up to 10 pairs of leaflets that in fall (autumn) turn yellow, orange and scarlet. It tolerates a wide range of conditions, including drought, heat, and alkaline soils. It will replace native plants, thereby altering the habitat for native animals and plants. Once mature, the female tree will produce large quantities of seeds, which are easily spread.

Vitex:  Vitex agnus-castus. A prawling plant that grows 10-20 ft (3-6 m) and about as wide. Branched flower clusters are produced on new wood in late spring and early summer in a great flush. Outcompetes native vegetation. Found in limestone outcrops and dry creek bed.

Japanese Honeysuckle:  Lonicera japonica. Introduced from Japan in the early 1800s for erosion control and as an ornamental. Semi evergreen, woody vine with simple, opposite leaves. Produces white to yellow (sometimes pink) fragrant flowers from April through September.

 Nandina:  Nandina domestica. Introduced from Asia and India in early 1800s. Widely planted as an ornamental, but now escaped and spreading from around old homes. Evergreen, erect shrub to 8 feet in height, with multiple bushy stems that resemble bamboo. Glossy, compound green or reddish leaves, white to pinkish flowers in terminal clusters and bright red berries in fall and winter.

Princess tree:  Paulownia tomentosa. Deciduous tree to 60 feet (18 m) in height and 2 feet (60 cm) in diameter with large heart-shaped leaves, fuzzy hairy on both sides, showy pale-violet flowers in early spring before leaves. aggressive ornamental tree that grows rapidly in disturbed natural areas, including forests, streambanks, and steep rocky slopes.

Quihoui privet:  Ligustrum quihoui. semi-evergreen to evergreen shrub, one to three meters high. Can out compete native vegetation and when not controlled can create a monoculture and change the understory of a forest. Morphologically similar Ligustrum sinense (Chinese privet), but can be distinguished by its narrower leaves, highly divaricate branching habit, and narrower inflorescence.