OKLAHOMA CITY - The monarch butterfly population continues the drastic decline that began about 20 years ago. And Oklahoma happens to be a primary location for monarch reproduction.

One lone weed is influencing when and where the Oklahoma Department of Transportation will mow along state highways.

That weed is the Milkweed. It's the sole monarch butterfly host plant.

So, researchers across the state, along with ODOT, are looking for ways to preserve the plant.

With the growing concern over monarch safety, a six-state collaborative was formed under the Federal Highway Administration.

“These states are partnering to see what best practices they can put into place to help maintain pollinator habitats. Specifically, for the monarchs, but other pollinators as well,” said ODOT Public Information Manager Lisa Shearer-Salim.

Why is Oklahoma apart of the collaborative? It is one of the first places where northbound monarchs will lay eggs in the spring.

“And then at some point, this late summer or fall, that migration will come back through, the fourth generation, and even sometimes a fifth generation will be produced in this area, on their way collectively to go back to Mexico,” said Dennis Martin with the Department of Horticulture.

The goal, now, is to mow less during the time the monarchs are laying their eggs

ODOT used to mow roadsides four times a season but in many places, it has cut back to doing only "safety mows" until late June or early July.

That means they will mow grass and weeds close to the roadway to help prevent fires and provide safe places to pull well over.

But ODOT’s main concern is the safety of drivers.

"ODOT's primary responsibility is always the safety of the traveling public. So, if there are areas where tall grass is getting out of control before it's time for that mowing, we will go ahead and mow,” said Shearer-Salim.

ODOT hopes that these changes will make a huge difference in the monarch population.