Florida is planting 15,000 milkweeds along highways to help monarch butterflies; the unused roadsides could become a 10,200-acre wildlife corridor
If you have driven through rural roads in northern Florida recently, you may have noticed new wildflower signs and patches of orange flowers growing along the roadside. These are not just for decoration. They are part of a large conservation effort to help monarch butterflies and many other pollinating insects.Scientists from the Florida Museum of Natural History and the Florida Department of Transportation have planted thousands of milkweed plants along roadsides across northern Florida. The project aims to create safe feeding and breeding areas for monarch butterflies, whose numbers have declined over the years.The team has already planted about 15,000 milkweed plants, and early results are encouraging. Scientists say the plants are growing well, and monarch butterflies have already started visiting them, Science X reported.
Butterfly corridors
The project is part of a wider programme led by the University of Illinois Chicago. The idea is to turn unused land along roads, railway tracks and power lines into natural corridors where monarch butterflies and other pollinators can find food and move safely between habitats.Florida joined the voluntary programme in 2024. Under the agreement, the Florida Department of Transportation plans to manage about 10,200 acres of roadside land in ways that support wildlife.The department first awarded a grant of $150,000 in 2023 to the research team to grow, plant and monitor 9,000 milkweed plants over three years. The project has now been extended until 2029, allowing another 6,000 plants to be added.“It’s been a lot of work but also really exciting to see,” said Jaret Daniels, curator of Lepidoptera at the Florida Museum of Natural History. “We’ve had good success with plant establishment, and we’ve seen monarchs using the plants already in the field.”
Why milkweed matters
Milkweed is much more than another roadside flower. It is the only plant on which monarch butterflies lay their eggs. Once the eggs hatch, the caterpillars, also called larvae, feed only on milkweed leaves. Without these plants, monarch butterflies cannot complete their life cycle.Milkweed flowers also produce plenty of nectar, the sweet liquid inside flowers that many insects feed on for energy. Bees, butterflies, moths, wasps, flies and several other insects depend on nectar, making milkweed an important food source.Daniels said roadsides are already maintained by people, so using them to support wildlife makes sense. “It’s a no-brainer,” he said. “We don’t have enough conservation lands to maintain pollinator populations through time in many areas, so we have to look to environments that we, as humans, manage every day. Roadsides are managed regardless, so why not do so in a way that confers greater benefits?”Milkweed belongs to a plant family called Apocynaceae. Many plants in this family produce natural toxic chemicals known as glycosides and alkaloids. These chemicals help protect the plants by making them difficult or dangerous for animals to eat. Most animals avoid these plants, but monarch butterflies have evolved special changes in their bodies that allow them to survive the toxins.
Helping long journeys
Adult monarch butterflies travel remarkable distances. A single butterfly can fly more than 100 miles (161 kilometres) in one day. These long journeys require a lot of energy. Butterflies regularly stop to feed on nectar from flowers growing in gardens, natural habitats and open spaces.The new roadside milkweed patches provide extra places where butterflies can rest and feed during these journeys.The benefits are not limited to butterflies. More flowering plants also provide food for bees, moths and many other pollinators. Birds and other wildlife that feed on insects may also benefit.Scientists say nearby farms growing crops such as blueberries and watermelons could also gain because more wild pollinators may visit the fields and help pollinate crops.
Finding milkweed species
The project is also helping scientists learn which milkweed species grow best beside roads. The researchers began with six native species but are now mainly using pinewoods milkweed (Asclepias humistrata) and butterfly weed (Asclepias tuberosa). Both naturally grow in dry, sandy soils, making them well suited to roadside conditions.“Both are upland, sand-loving species that would normally be found in pinelands and sandhills,” Daniels said.Growing pinewoods milkweed is not easy. The plant develops a long main root, called a taproot, which needs deep pots while it is being grown. Since these plants are not widely sold, the research team created its own supply chain.Scientists collect seeds from wild plants before they are carried away by the wind. The seeds are then sent to the University of Florida Native Plant Nursery, where staff and volunteers grow them into young plants.“The last batch of seed we gave them had about a 98% germination rate, and we’ve seen really good establishment of these plants in the field,” Daniels said. “The Native Plant Nursery has been an invaluable partner in this project.”The team buys butterfly weed from a commercial nursery before planting all the young plants during winter, when cooler weather helps them settle into the soil.
