Minidoka County, Idaho - Official Website

Home

Departments

Calendar

Photo Gallery

 
Minidoka County, Idaho - Official Website

Home

Departments

Calendar

Photo Gallery

 
[includes/nav/main.htm]

 

Home :: Weed Department :: Noxious Weeds Poison Hemlock

Poison Hemlock
Apiaceae (= Umbelliferae), the parsnip family

Background

Poison HemlockPoison hemlock is native to Europe. It contains highly poisonous alkaloids toxic to all classes of livestock and humans. It has poisoned many who have mistaken it for parsley. Poison hemlock is often found on poorly drained soils, particularly near streams, ditches, and surface water.

Description

Poison HemlockPoison hemlock is a biennial that grows up to 10 feet tall. Stems are stout, hollow, ridged, and mottled with purple spots. Leaves are shiny green, 3 to 4 times pinnately compound, and clasp the stem at the obvious nodes. Crushed foliage has a disagreeable, mousey odor. Flowers are small, white, and borne in umbrella-shaped clusters about 3 inches across in early summer. Seeds are ridged and flattened, with 2 seeds borne together. The plant has a thick, white taproot.

Distribution

Poison Hemlock distribution mapIt grows throughout the U.S. except from eastern Montana to northeastern Minnesota and south to Nebraska. It has an extensive presence in Idaho.

Control

A biological control agent (a defoliating moth) provides good to excellent but inconsistent control. Herbicides are also available.

 

1999 University of Idaho: Text and photographs for these pages from Idaho's Noxious Weeds, by Robert H. Callihan and Timothy W. Miller (revised by Don W. Morishita and Larry W. Lass).

Please contact: Ag Publishing, University of Idaho, Moscow, Idaho 83844-2240; 208 882-7982 visit the Resources for Idaho website at http://info.ag.uidaho.edu, for more information about this or other publications.

 

 

 

-- Home :: Commissioners :: Departments :: Judicial ::Services ::  Links --

-- Commissioners' Proclamation --
-- Terms of Use --
--  Site Map --

2010 Minidoka County, Idaho
- Web Site by Surf The Snake -
 

 

Home :: Weed Department Idaho's Noxious Weeds

Idaho has about 800 of the nations 2,000 weed species, most of which are alien to the state. Idaho's noxious weeds have been introduced from other regions. We do not have the natural systems to keep them in check. Importing natural controls is not possible for all weeds, and it takes decades to and vast resources to introduce naturals controls. As a result, noxious weeds overwhelm native plant communities and disturbed areas, spreading steadily year by year. Several species that were previously unreported have been found each year over the last 10 years. Recognition of invaders is the first step in dealing with them.
Noxious weeds spread rapidly as if a cancer in the natural system. They reproduce, multiply, and spread as an explosion of environmental pollution, in slow motion, While many pollutants tend to decay and become dilutes, weeds become concentrated and spread to new locations. Once the habitat becomes infested it may never recover to a native community even with intensive management
Prevention and inspection are the most economical management system for reducing the rate of noxious weed spread. Once noxious weeds have become established expect to spend $30 to $70 per acre for management on your land or in higher taxes for their management on public land.

What is a noxious weed?

Noxious weeds are plant species that have been designated "noxious" by law. The word "noxious" simply means deleterious, and all listed weeds are deleterious by definition. There are hundreds of weed species in Idaho; however, only 35 are designated noxious by Idaho law as of 1977. There are hundreds of weeds species in Idaho; however, only 35 are designated noxious by Idaho Law as of 1997. Currently, the Idaho Department of Agriculture uses the following criteria for designation of a noxious weed:
  1. It must be present in but not native to Idaho.

  2. It must be potentially more harmful than beneficial to Idaho.

  3. Eradication must be economically physically feasible.

  4. The potential adverse impact of the weed must exceed the cost of control

The purpose of the Idaho Noxious Weed Law is to protect lands within  the state from invasion by noxious weeds. The Idaho Noxious Weed Law requires landowners to eradicate noxious weeds on their land, except in special management zones.

Managing Noxious Weeds

The procedure to control noxious weeds depends on the species of weed, the habitat, the surrounding environment, and the availability of equipment, materials and personnel. Eradication and restoration require that weeds be killed. Their very nature make that difficult, for they are invaders by nature and do not succumb to control except at great cost.

Guidelines to help lessen the spread of noxious weeds in Idaho

  • Avoid driving in noxious weed infested areas. Seeds can become stuck in tire treads or mud on the vehicle and be carried to unaffected areas.

  • Don't transport flowering plants that you cannot identify.

  • If you find a small number of isolated noxious weeds that have no flowers or seeds, pull the weeds and leave them where you found them to dry out.

  • If you find noxious weeds and they have flowers or seeds, pull them, place them in a plastic bag or container to avoid spreading seeds, and either burn them or dispose of them in a sanitary landfill.

  • Report newly-found noxious weeds to the county weed superintendent or county extension office. If you need help in identifying new weeds here is the procedure.

  

1999 University of Idaho: Text and photographs for these pages from Idaho's Noxious Weeds, by Robert H. Callihan and Timothy W. Miller (revised by Don W. Morishita and Larry W. Lass).

Please contact: Ag Publishing, University of Idaho, Moscow, Idaho 83844-2240; 208 882-7982 visit the Resources for Idaho website at http://info.ag.uidaho.edu, for more information about this or other publications.

 
 

-- Home :: Commissioners :: Departments :: Judicial ::Services ::  Links --

-- Commissioners' Proclamation --
-- Terms of Use --
--  Site Map --

2010 Minidoka County, Idaho
- Web Site by Surf The Snake -