Federal officials want landowners in Illinois and nine other states to grow milkweed to boost the population of monarch butterflies. The U.S. Department of Agriculture is due to spend $4 million in 2016 to help farmers and others plant milkweed and other nectar-producing plants. The agency wants to re-establish habitats for monarchs and pollinators in general. Milkweed is essential for monarchs since it is the only plant on which the butterfly will lay its eggs. It takes three to four generations for the monarchs to migrate to roosting spots in mountains of central Mexico.