June 24th-30th is Weed Awareness Week. Why should you care? Invasive plants have the ability to outcompete native vegetation in a variety of ways such as an increased frost tolerance, swift germination, affixation of nitrogen or ability to increase salt content in soils, allelopathic properties (releasing chemicals from roots to suppress surrounding plants), or creating shade thereby discouraging germination or growth of native plants. Many invasive plants are hosts to diseases and other pests that, in turn, are harmful to our local habitats.
There are a few invasive plants found in every community on the peninsula that can have serious economic or environmental harm, or even threaten human health. Here are three species that are likely to have particularly harmful effects on the Kenai.
Reed Canarygrass is an invasive grass that is used as forage on the peninsula. This species is a tall, robust grass that is easily identifiable in the fall, as it is the last grass to stay bright green even after mild frosts. It grows up to six feet tall, and can grow in such dense colonies that it slows water flow in low-gradient streams, and has reduced juvenile salmon habitat in the Pacific Northwest. The CWMA recently developed a strategic plan for the control of Reed canarygrass. It is currently found in small patches near the schools.
Orange hawkweed is another problem species in our local area. It is an ornamental plant that has proven its ability to spread beyond intended borders. It has a rosette of excessively hairy leaves, which exude a white liquid when broken, and several orange blossoms on a single stem. There are no native orange composite flowers in Alaska – so if you see one in a natural area, it is non-native and perhaps invasive.
Bird vetch appears similar to the native beach pea found in our community, but it has tendrils that assist it in climbing over and smothering other vegetation. It has many narrow leaflets, grows up to 8 feet, and blocks the sunlight from small trees, shrubs, and forbs. The flowers are purple, all on one side of the inflorescence (flower head), and bloom in July. This species is of a major concern for our community as it has become established at the middle school. Please come help us remove this invasive plant in the second annual “Weed Smackdown” on Saturday June 30th from 11-1.