A fast-growing tree favored by a dangerous insect and a plant poisonous to livestock and humans are candidates to be banned from Washington.
The State Noxious Weed Control Board has recommended prohibiting selling or bringing into the state tree-of-heaven and poison hemlock.
Native to China, tree-of-heaven (Ailanthus altissmia) provides the primary mating habitat for the spotted lanternfly, another Asian native. Spotted lanternflies feed on many other plants, including hops, grapes, cherries and apples.
They are a threat to orchards, according to the USDA. The spotted lanternfly was found in Pennsylvania in 2014, the first U.S. detection. Since then, spotted lanternflies have infested Delaware, Maryland, New Jersey and Virginia.
Lanternflies have not been detected in Washington. They could, however, spread by laying eggs on property moving west, according to the USDA.
Banning tree-of-heaven would be a pre-emptive strike, according to the Washington State Department of Agriculture.
Tree-of-heaven infestations have been documented in 17 of the state’s 39 counties. The Central Washington counties of Chelan, Douglas and Klickitat have the worst infestations, according to the weed board.
Poison hemlock (Conium maculatum) can be fatal to sheep, cattle, swine and horses, according to the USDA.
Every county, except Grant County, has patches of poison hemlock, according to the weed board. “It was originally an ornamental plant, and it just got loose,” said Mary Fee, weed board executive secretary.
Infestation levels are highest in Pierce and Whatcom counties in Western Washington, and Columbia County in Eastern Washington.
People can participate in formulating a rule by contacting Brad White, assistant director of the agriculture department’s Plant Protection Division, or Cindy Cooper, plant services program manager.