With its yellow flowers, narrowleaf hawksbeard resembles a dandelion, but it is an invasive weed that can reduce crop yields significantly.

It grows 2 to 3 feet tall, and a single plant can produce up to 50,000 seeds. It’s spread by the wind. It can start out on the edge of a field in one year, and if a strong wind blows the seeds around, it can infest the entire field the following year.

Narrowleaf hawksbeard, which is native to Siberia and much of Eurasia, was not much of a problem in North Dakota before 2017. However, that year, several fields had infestations, and it was named the weed of the year in 2018.

It’s a winter annual, which means it germinates in the fall and develops quickly in the spring. As a result, it outcompetes crops for nutrients and moisture.

The good news is that it can be controlled with herbicides, according to weed scientist Brian Jenks, who is based at the North Central Research Extension Center near Minot.

“The biggest challenge is in lentils and chickpeas, where we don’t have very many herbicide options,” he says.

The key is to control it with herbicide in the fall and again in the spring before planting a crop.

“That should control 95% to 98% of it,” Jenks says. “If you wait until spring, you could miss it entirely.”

Producers will need to use higher than normal rates of herbicide, and they may need to add another herbicide to their usual mix.

The goal is to control the narrowleaf hawksbeard before it goes to seed. Unlike weed seeds that can remain dormant for years, narrowleaf hawksbeard seeds have little longevity.

“If we can control them in one year, we tend to have very clean fields the next year,” Jenks says.

FOR MORE INFORMATION:

Brian Jenks, 701-857-7677, brian.jenks@ndsu.edu

Additional Link:

Controlling Winter Annual Weeds Video