Native to China, this tree was brought to North America in 1784 as an ornamental. Although its wood is weak and brittle, it is resistant to disease and insects and grows quickly, even in poor soil. It spreads through its roots and the roots produce a toxin that inhibits native plant growth. This invader is nearly impossible to kill. Since escaping cultivation, tree of heaven has spread through urban areas and along streams, thickets, roadsides, and railroads. It competes with native plants and hardwood trees.