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Poison Hemlock
Apiaceae (=
Umbelliferae), the parsnip family
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Background
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 Poison
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.
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Description
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 Poison
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.
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Distribution
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 It
grows throughout the U.S. except from eastern Montana to northeastern
Minnesota and south to Nebraska. It has an extensive presence in Idaho. |
Control
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A biological control agent (a
defoliating moth) provides good to excellent but inconsistent control.
Herbicides are also available.
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© 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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Orange Hawkweed (king devil,
red devil, devil's paintbrush)
Asteraceae (= Compositae), the aster family
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Background
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 Orange
hawkweed is native to Europe. Distribution of this weed has likely been
assisted by flower enthusiasts due to its beauty. Orange hawkweed spreads by
seeds, stolons, and
rhizomes, and generally
inhabits moist grasslands. |
Description
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Orange hawkweed is a perennial weed with shallow,
fibrous roots. Leaves are hairy, spatula shaped, up to 5 inches long, and
almost always basal. Extensive stolons create a dense mat of hawkweed
plants that practically eliminates other vegetation. Stems are usually
leafless, although occasionally a small leaf appears near the midpoint.
Stems may reach a height of 1 foot and bear up to 30, 1/2-inch flower heads
near the top. Flowers are red to orange and appear in late May or June. Stems
and leaves exude a milky latex when cut or broken. Seeds are tiny and
plumed.
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Distribution
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 Orange
hawkweed is found in many eastern states and also from western Washington to
Wyoming.
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Control
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No biological control agents are available for orange hawkweed. When
selective herbicides are applied in
the spring and followed with nitrogen fertilizer, grass competition can keep
this weed suppressed.
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© 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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