The issue: Cutleaf vipergrass
Cutleaf vipergrass (Scorzonera laciniata) is an invasive biennial to short-lived perennial from Eurasia and Africa. It very closely resembles the western salsify with a few minor differences. The salsify flower stem gradually narrows down the stem, the cutleaf vipergrass flower stem constricts immediately after the flower. Western salsify has grass-like leaves, the cutleaf vipergrasss has deeply lobed leaves. The flower and seed head of vipergrass are a little smaller than salsify. In size, the vipergrass flower and seed head are between the salsify and dandelion. It has a tap rot and hollow stem with milky sap.
Cutleaf vipergrass is often found in disturbed sites, fallow fields and on roadsides. There are no known populations in Idaho yet, but it has been identified in Montana, Wyoming Colorado, and several northern Utah counties, so be on the lookout.
Cutleaf vipergrass reproduces only by seed and the parachute-like pappus helps with wind dispersion, so eliminating seed production is key to control.
Integrated pest management options:
· Prevention: Feed weed-free hay, especially from out-of-state sources. Keep ditch banks free of seed-producing weeds.
· Mechanical: Hand-dig small patches before flowering, removing as much root as possible; mow regularly before flower formation.
· Cultural: Manage land to improve competitiveness of beneficial plants; don’t overgraze pastures and rangeland.
· Biological: None.
· Chemical: Little research has been done on herbicide effectiveness for cutleaf vipergrass, but a combination of 2,4-D and dicamba should work as well as it does on western salsify. It is unlikely you will find this specific weed on a herbicide label, but be sure the landscape situations are listed. Always read and follow herbicide label directions.
Combine them: Combine different IPM options over a period of years to help improve the effectiveness of your efforts.