How to Effectively Treat Wild Parsnip

Identify wild parsnip: Make sure you are able to identify wild parsnip.  Wild parsnip is a biennial, with first year plants having distinctive shaped close to ground, and second year plants up to 3-4 feet tall with a rosette which develops yellow flowers and then goes to seed, with one plant having up to hundreds of seeds.

Check out our wild parsnip fact sheet  

Beware of wild parsnip sap: The sap of wild parsnip can cause serious skin burns if the skin is then exposed to sun, so make sure to avoid any contact with the plant.   Use long handled clippers when cutting 2nd year plants, and have gloves/long pants/long-sleeved shirt on.  If you think you had exposure of the skin, wash that area well with soap (?anti-poison ivy) and avoid any sun exposure to that area for at least several days.

Treatment methods:

Mowing/cutting stems: Mowing or cutting stems with long handled clippers prior to going to seed can be effective, but the area needs to be mowed for several years to control plants that grow from first year plants or from seeds (which can be viable for years).  Sometimes a clipped plant will develop another flowering then seed head, so that should be mowed/clipped again prior to going to seed.  Avoid mowing after plants have gone to seed, as that can disperse the seeds.  Encourage public works departments to mow right-of-ways that have wild parsnip prior to the plants going to seed.
Cutting and disposing plants gone to seed: Once the plant has gone to seed, it is best to clip the plant, place in large plastic bag, and dispose of bag at transfer station.  Make sure the plants with seed are not transported to other sites where they could grow
Pesticide spray: Pesticide foliar spray to first year plants can be effective, using about 3% glyphosate with surfactant.  We are trying to determine optimal pesticide concentration, and also whether pesticide spray to second year plants can be effective if done early, or whether pesticide spray to the leaves lower than where clip plant will prevent growth of a second flowering/seed head.

RIIPP and wild parsnip

RIIPP began treating wild parsnip at several sites in Inlet starting in 2015 with treatments late June/early July when plants in flower, and again in mid-late August when plants gone to seed but prior to dropping seed.  The first treatment includes  cutting stems above first leaves near ground and foliar spray to first year plants and to leaves near ground of cut plants.  The second treatment in August includes cutting/bagging/disposing of plants that have gone to seed, and foliar spray to first year plants.  This has been very effective, with some sites of hundreds to thousands of plants now having dozens of plants, and sites with a few to 20 plants having none to a few plants after two to three years of treatment.
Starting in 2018, RIIPP has begun efforts to treat wild parsnip in more areas from Old Forge to Inlet to Blue Mountain Lake.  We have obtained permissions to treat along NYS DOT, Herkimer County, Hamilton County, and some town right-of-ways and property owners.  Lack of sufficient funds limits these efforts by RIIPP, so efforts by private owners and towns will be essential.