About

In this project, tracking a plant means recording how it changes over time. In particular, when do key life cycle events occur over the course of the growing season? How can volunteers become plant trackers? The Pesky Plants program offers free training and resources showing what to look for, how to stay safe while working around these plants, and how to share observations. From March through October, volunteers visit their patch of plants at least once a week to make observations and report what they see using Nature’s Notebook or paper datasheets. This project fits within a greater discipline called phenology, the study of recurring life cycle events of plants and animals. The Pesky Plants program partners with the USA-National Phenology Network and is associated with the Minnesota Phenology Network.

An invasive plant is one that comes from another part of the world and causes harm in its new-found environment. Wild parsnip and Japanese knotweed are highly damaging invasive plants in North America.

The sap of wild parsnip contains a chemical that causes severe skin burns. Protective clothing is required when working around wild parsnip, and one must take care not to break any part of the plant in order to avoid exposure. (Click here for safety information.) Wild parsnip forms dense monocultures that displace native plants and degrade habitats for wildlife.

Japanese knotweed spreads aggressively and can damage property. It sends out underground roots and rhizomes that exploit cracks or weaknesses in pavement, building foundations, retaining walls, drainpipes, and other features of the built environment. Japanese knotweed reproduces vegetatively, meaning that escaped plant fragments (e.g., a piece of a shoot or root) can grow into clone plants that colonize new areas and form dense stands. Knotweeds can contribute to poor water quality by displacing native plants that would otherwise stabilize soils along river and stream banks.

Because of the harms they cause, wild parsnip and Japanese knotweed are targets for management and removal.

Removing these plants is complicated work that must be timed with plant life cycle stages. For example, wild parsnip plants can be mowed before they flower. However, if plants within the treatment area have seeds, then mowing exacerbates the problem by helping the plant spread. In order to improve management of these plants, we need to understand them better, especially the timing of their annual cycles. Join the effort to understand wild parsnip and Japanese knotweed by volunteering with Pesky Plant Trackers. Volunteer observers learn to identify these plants, collect scientifically valuable information, and ultimately, help restore Minnesota environments.

Volunteer activities do not involve removing plants.

Pesky Plants staff work closely with partners at the Minnesota Department of Agriculture to ensure that research methods comply with Minnesota Noxious Weed Law and research goals address knowledge gaps.

Related resources:

• Wild parsnip biennial lifecycle and treatment timing (PDF)
• Knotweeds perennial lifecycle and treatment timing (PDF)

Land managers who control invasive plants need to predict when plants flower, form seeds, go dormant, or enter other key phases. Making predictions is difficult because within a single species, individual plants develop at different rates depending on where they are and year-to-year variations in weather. Moreover, climate change causes observable shifts in plant phenology.

To improve our predictions, we need more observations, especially observations from many different places. Your observations will be analyzed by the Pesky Plants research team to create predictive models. Those models will be integrated into USPEST.org, where land managers can calculate appropriate dates for mowing, applying herbicide, and other management efforts.

By volunteering, you are part of a larger investigation into the phenology of wild parsnip and Japanese knotweed. Managing these plants requires an understanding of how their growth varies with environmental conditions. One way to build that understanding is to involve citizen scientists who share observations from many locations. A second way is to run experiments in controlled environments. The overarching research plan combines both approaches, and can be thought of as having three components:

1. Pesky Plant Trackers Citizen Science: Participants monitor plants growing in their local environments and share what they see using Nature's Notebook.
2. Field Sites: Researchers established five field experiments at facilities spread across Minnesota. Each site has a small team of Field Site Volunteers who monitor plants and collect phenology data.
3. Growth Chamber Experiments: The core team observes wild parsnip and Japanese knotweed plants growing in controlled, indoor facilities called growth chambers. Each chamber runs a distinct treatment, or environment with a fixed temperature and light cycle.

These three components allow researchers to build a robust, multidimensional understanding of wild parsnip and Japanese knotweed phenology.