This campaign has ended, read more about the results below!


This campaign engaged observers in reporting initial growth, flowering, and fruiting of three non-native invasive species in the Midwest and Northeast - wild parsnip, Japanese knotweed, and Bohemian knotweed.

Wild parsnip, a carrot-like perennial that can reach 6 feet tall, poses human health risk due to a phototoxin produced by the leaves. Skin contact with the leaves followed by exposure to sunlight will cause severe blistering. Parsnip can be managed by mowing, but only prior to mature seed development to prevent spread, or herbicide application during specific stages of plant growth. Mowing too late can help to spread seeds.

Japanese knotweed and Bohemian knotweed are aggressive, bamboo-like shoots that can reproduce without seed. Control is extremely difficult, but applying herbicides at certain stages of knotweed development can maximize their effectiveness and stop infestation.

Data collected as part of this campaign will enable land managers to correctly time management activities aimed at controlling these species. Researchers will use the phenology data collected to understand relationships between accumulated temperature and life cycle events like initial growth and flowering. The researchers will then build models that use forecasted weather to predict the timing of these life cycle events.

We have ended the phenology observation phase of the Pesky Plant Trackers campaign. However, we still encourage observations of these species in Nature's Notebook!

See results of this campaign from 2022.

We invite you to take the Pesky Plant Trackers online training course for an in-depth tutorial on how to make observations on Japanese knotweed and wild parsnip. This course was designed by Abbie Anderson, who was the Program Coordinator for Pesky Plant Trackers at the University of Minnesota from 2020-2022, and other members of the UNM team. The course should take approximately four hours to complete. 


Pesky Plant Trackers was a partnership between University of Minnesota's Department of Forest Resources and the USA National Phenology Network. This research was funded by the Minnesota Invasive Terrestrial Plants and Pests Center and is led by Dr. Rebecca Montgomery. Our team included experts on the control and regulation of invasive plants.