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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.

 

 

 

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Home :: Weed Department :: Noxious Weeds » Puncturevine

Puncturevine
(goathead, Mexican sandbur, Texas sandbur, ground bur-nut, land caltrop)
Zygophyllaceae, the caltrop family

Background

PuncturevinePuncturevine is a naturalized invader from Europe. It spreads by seed and is most often found on sandy, dry, or gravelly sites. Puncturevine produces sharply pointed burs that stick painfully in bare feet and cause bicycle flats, reducing the recreational use of many areas. Seeds may puncture even light truck tires.

Description

Puncturevine is a prostrate annual that forms dense mats up to 4 feet across. Leaves are opposite and pinnately compound with 4 to 8 pairs of oval, hairy, 1/2-inch long leaflets. Stems branch from the base and from leaf axils and are slender and hairy. Flowers are 5 petalled, yellow, 1/2 inch wide, and borne singly in leaf axils from midsummer until frost. Fruits are roughly circular, splitting into 5 sections, each with 2 large, divergent spines. These tack-like burs contain up to 4 seeds.

Distribution

Puncturevine distribution mapPuncturevine is throughout the U.S., except for the northern tier states from Montana to Maine

Control

Biological control agents (seed and stem boring weevils)
provide fair to good control in Oregon, but control levels are uncertain in Idaho. Herbicides are available for control of this weed.

© 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 -