One of the four species Door County has focused efforts on is Wild Parsnip. Wild parsnip is an invasive species originally introduced as an agricultural commodity. It escaped cultivation and rapidly spread throughout the United States. Wild parsnip is notorious for the burns that an unsuspecting passerby can receive when sap from the plant gets on skin and is introduced to sunlight, resulting in photodermatitis. At the start of the summer, Door County Soil & Water hired two seasonal employees, Sam Hoffman & Tina Lee, to aid in invasive species monitoring, control, and outreach efforts throughout Door County. This year Soil & Water Conservation staff have controlled 12 acres of wild parsnip through shovel cutting and helped facilitate an additional 25 acres of control by a private contractor, resulting in 61.3% of the 60.4 acres of wild parsnip inventoried in Door County this year being controlled. Wild parsnip is a biennial and seed banks can be persistent, however; continued treatment efforts can result in controlled populations.
Another one of the four species Door County has focused control efforts on is Japanese knotweed. This year 1 acre of Japanese knotweed out of 5.1 acres inventoried has been treated by Door County Soil & Water Staff and an additional 1 acre will be controlled by a contractor resulting in 39% of the inventoried populations of Japanese knotweed being controlled in 2020. The most common way of introducing Japanese knotweed is through redistribution of a root or shoot fragments. One small fragment left unchecked can result in a tap root 6’ deep and stout rhizomes spreading out 65’. When stressed, some studies indicate knotweed can go dormant up to 25 years! For more information please check out the June 2020 DCIST invasive species highlight section .
