Herbicide Forum December 2015 New Weeds and Controls Herbicide Forum December 2015

Aegopodium podagraria Bishop’s goutweed 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 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 CARPEN Riparian, wetland, other moist areas Seeds June-July Also spreads by rhizomes Contaminant in bird seed? 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 Biennial To 30 in. tall Sap Deeply lobed leaves with long petioles

Chelidonium majus Greater celandine