Transcript New Weeds and Controls

New Weeds and Controls
Herbicide Forum
December 2015
Aegopodium podagraria
Bishop’s goutweed
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Basal leaves, triternate
Spreads by rhizomes
Seed dispersal unimportant
Invades woodlands, forest
edges, open areas
• Prefers partial shade
• Widely sold as a ground
cover
Aegopodium podagraria
Bishop’s goutweed
Aegopodium podagraria
Bishop’s goutweed
• “where it hath once taken roote it will hardly be
gotten out againe, spoiling and getting every yeere
more ground, to the annoying of better herbes”
(Gerard, late 1500s)
• “with his roots stamped and laid upon members that
are troubled or vexed with gout, swageth the paine,
and taketh away the swelling and inflammation
thereof, which occasioned the Germans to give it the
name of Podagraria, because of his virtues in curing
the gout.” (Gerard)
Aegopodium podagraria
Bishop’s goutweed
• Manual control: hand pulling, raking, digging;
remove all rhizomes and roots
• Solarize: cover in spring
• Chemical:
– Glyphosate in spring or summer?
– Older leaves “resistant”?
– Multiple treatments necessary?
• Non-variegated form may be more difficult to
control
Barbarea vulgaris
Yellow rocket
• Biennial (basal rosette 1st
year)
• Basal leaves large
terminal lobe
• Stem leaves without
stalks, may have auricles
• Winter growth
• Seed dispersal
• Likes sun, open areas
Barbarea vulgaris
Yellow rocket
Barbarea vulgaris
Yellow rocket
• St. Barbara’s herb (all members of the
genus are Herba sanctae Barbarae)
• Vitamin C and other nutrients
• Widely cultivated
The absence of fresh food during the winter
made scurvy prevalent; in the spring, people
eagerly sought "scurvy grass" to eat.
"Our Legal Heritage, 5th Ed." by S. A. Reilly
Barbarea vulgaris
Yellow rocket
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Rapid establishment but poor competition?
Seed longevity 10+ years?
Manual: hand pull
Mechanical:
– mow to prevent seed set
– Cultivate at rosette stage
• Chemical: spray rosettes (fall, winter, spring)
Carex pendula
Drooping sedge
• Triangular stem
• Exceptionally long
inflorescences (to 6 in.)
• Large plant (3+ feet)
Carex pendula
Drooping sedge
• Riparian, wetland,
other moist areas
• Seeds June-July
• Also spreads by
rhizomes
• Contaminant in bird
seed?
CARPEN
SCIMIC
Carex pendula
Drooping sedge
Even the ferociously elegant sedge, Carex
pendula, is a brute. It scatters seed everywhere...
Lovely, yes, but I broke two spades trying to
uproot one big clump. Destroy every seedling or
buy spades by the dozen.
David Stuart, The Guardian.com
Carex pendula
Drooping sedge
• Control methods??
– “I'm going to have a bonfire on top of it.”
Linaria vulgaris
Yellow toadflax
• Perennial, rhizomatous
• Typically 1 ft. tall
• Snapdragon-like yellow
flowers are spurred
• Narrow leaves
• Hybridizes with
Dalmatian toadflax
Linaria vulgaris
Yellow toadflax
Dalmatian
Yellow
Linaria vulgaris
Yellow toadflax
• Manual: hand-pull small seedlings
• Mechanical: not recommended (mowing and
grazing help it spread)
• Biocontrol: weevil, effectiveness unknown
• Chemical: several options
– Dicamba, 2,4-D, imazapic
– Glyphosate (1.5 to 2 percent in early spring)
– Imazapyr (relatively high rate)
– Surfactant necessary, waxy leaves
Chelidonium majus
Greater celandine
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Biennial
To 30 in. tall
Sap
Deeply lobed
leaves with long
petioles
Chelidonium majus
Greater celandine