Many species prized for gardens-because they are fast-growing, have unique blossoms, or grow well in poor soils-also may be successful invaders, such as English ivy, planted for its ability to control unstable soils, or butterfly bush, with its showy purple flowers. A wide variety of invasive plants are sold at Washington nurseries, home improvement centers, and on the Internet for their ornamental value or their perceived value in helping with erosion control or serving as a wind block.
These include common crupina, common reed, Dalmatian toadflax, garlic mustard, giant hogweed, hawkweeds, Himalayan blackberry, hydrilla, knotweeds, kochia, kudzu, parrotfeather, purple loosestrife, saltcedar, Scotch broom, Scotch thistle, spartina, and water chestnut. Some plants are sold in Washington despite being on the state quarantine list, meaning it is prohibited to transport, buy, sell, offer for sale, or distribute those plants, plant parts, or seeds.
In addition, infested trees, tree fruit, nursery plants, or other plant products that are transported across distances may introduce exotic apple fruit pests or wood-boring insects.
If you’re a gardener or landscaper, you can help prevent the spread of invasive species by avoiding purchasing, selling, trading, planting, or releasing non-native species.
For more information, see the following Web sites: