Invasive Plants and Exotic Weeds of Southeast Alaska
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Invasive Plants and Exotic Weeds of Southeast Alaska Tom Heutte, Biological Technician, USDA Forest Service, State and Private Forestry, Forest Health Protection, Juneau, Alaska Elizabeth Bella, Ecologist, USDA Forest Service, Chugach National Forest, Seward, Alaska. Technical Review Jamie Snyder, University of Alaska Cooperative Extension Service, Anchorage, Alaska Michael Shephard Forest Ecologist, USDA Forest Service, Forest Health Protection, Anchorage, Alaska Quarter mile-long knotweed patch on beach near Juneau - 1 - Introduction....................................................................................................................... 4 Weed management, herbicides and safety...................................................................... 8 Glossary ........................................................................................................................... 11 How to use this guide. ..................................................................................................... 14 Species Accounts Brass buttons..................................................................................................................... 15 Pineapple weed ................................................................................................................. 16 Oxeye daisy....................................................................................................................... 17 Russian knapweed............................................................................................................. 18 Spotted knapweed ............................................................................................................. 20 Canada thistle.................................................................................................................... 22 Bull thistle......................................................................................................................... 24 Smooth hawksbeard.......................................................................................................... 26 Annual hawksbeard........................................................................................................... 27 Orange hawkweed............................................................................................................. 28 Narrowleaf hawkweed ...................................................................................................... 31 Spotted catsear .................................................................................................................. 32 Perennial sowthistle .......................................................................................................... 33 Prickly lettuce ................................................................................................................... 35 Nipplewort ........................................................................................................................ 37 Hawkbit............................................................................................................................. 38 Tansy ragwort ................................................................................................................... 39 Common tansy .................................................................................................................. 41 Garlic mustard................................................................................................................... 42 Turnip................................................................................................................................ 44 Sweetrocket....................................................................................................................... 45 Scotch broom .................................................................................................................... 46 Sweetclover....................................................................................................................... 48 Clover................................................................................................................................ 49 Orchard grass .................................................................................................................... 50 Foxtail barley .................................................................................................................... 51 Reed canarygrass .............................................................................................................. 52 Smooth cordgrass.............................................................................................................. 54 Timothy............................................................................................................................. 56 Foxglove ........................................................................................................................... 57 Toadflax ............................................................................................................................ 58 Brittlestem hempnettle...................................................................................................... 60 St. Johnswort..................................................................................................................... 61 Purple loosestrife .............................................................................................................. 62 Forget-me-not ................................................................................................................... 64 Plantain ............................................................................................................................. 65 Japanese knotweed............................................................................................................ 66 Creeping buttercup............................................................................................................ 68 Common chickweed.......................................................................................................... 69 - 2 - Giant Hogweed ................................................................................................................. 70 Himalayan balsam............................................................................................................. 71 Spurge laurel ..................................................................................................................... 72 References........................................................................................................................ 73 Websites ........................................................................................................................... 74 Scientific Names, Synonyms, Common Names, NRCS Codes.................................... 75 Noxious Weeds as Listed Under the Alaska Administrative Code .................................. 80 - 3 - Introduction: Southeast Alaska remains one of the most pristine landscapes in Alaska, a state renowned and celebrated for its protected wildlands, lush forests, open tundra and vast expanses of wilderness. In the past, Alaska’s wildlands, with their cool climates and remote locations, were considered relatively immune to invasion by nonnative plant species. Today, although there are relatively few invasive plants found in the lands where we live, work and play, we are starting to discover newly established exotic plants gaining a foothold across the state. Southeast Alaska residents and visitors alike have a unique opportunity to protect our wildlands from irreparable damage caused by invasive species. Biologists throughout the world have become acutely aware of the threat posed by invasive species as they encroach upon natural areas. Invasive species blight landscapes, push rare species to the brink of extinction, and cause economic harm all over the world. Millions of acres of land in the lower 48 states and Hawaii have been irreparably harmed by invasive plants. The growing tourism industry in Alaska, as well as oil and gas development, international trade and a burgeoning human population all contribute to an increase in invasive plant introduction and spread. Native wildflowers, forested ecosystems, riparian systems, and wildlife are all threatened by invasions of exotic species entering the state. This book is a cooperative effort between the Alaska Soil and Water Conservation District, The USDA Forest Service, and the US Fish and Wildlife Service. The purpose of this book is to educate as many people as possible around the state to look for and to identify invasive species in their own communities and throughout our Alaskan wildlands. The reader of this book can be part of an early warning network to alert scientists, land managers, and community organizations to the presence of invasive species as they are introduced, become established, and begin to spread. Early detection and quick action are the best basis for a strategy for dealing with invasive plant threats in Alaska. Please use this book as a starting point in educating yourself about which plants are native to our area, which are common roadside weeds, and which pose serious threats to our landscape. What makes a plant invasive? Cousens and Mortimer (1995) ask what gives invasives the ability to reduce biodiversity in natural systems and interfere with other systems. Invasiveness can be defined