A fall project at the Lady Bird Johnson Wildflower Center is encouraging homeowners and businesses to plant milkweed to serve as monarch caterpillar nurseries in the spring. 

In June 2015, the Wildflower Center, using funds from the U.S. Fish and Wildlife Service, founded Project Milkweed in order to promote planting milkweed in Central Texas.

Every October, North American monarch butterflies migrate south, traveling up to 3,000 miles in search of warmth, according to the United States Department of Agriculture. When they return north in the spring, monarch butterflies lay their eggs on milkweed, which later serves as the caterpillars’ sole source of food.

According to Wildflower Center plant conservationist Minnette Marr, habitat fragmentation poses a major threat to monarch butterflies. Partly because of herbicides, milkweed populations across Texas have dwindled. 

“The main goal was to improve habitat for monarch butterflies during their migration through Texas,” Marr said. “This particular project focused on increasing the availability of milkweed seeds for commercial and volunteer growers in four eco-regions in North Central Texas.” 

The project targeted four species of milkweed: antelope horns, green milkweed, green comet milkweed and zizotes. 

“With the help of volunteers throughout the four ecoregions, we packaged about 200,000 seeds for commercial and volunteer growers,” Marr said. “For three of the four target species, we have already distributed all of the seeds that were collected … Antelopehorn seeds are still being disseminated.” 

It’s difficult to determine the effect of Project Milkweed, according to Marr, who said she has to wait a long time for grower feedback. Project Milkweed will start analyzing the data from milkweed growers in 2018 and 2019. 

In the meantime, Marr is researching talayote, another larval host for monarchs in South Texas. Her team collected talayote seeds from Historic Stagecoach Park in Buda and is sharing the seeds with volunteers to test talayote as a larval host.

“The vine is more tolerant of dappled shade than most species of milkweed,” Marr said. “If we can determine that talayote is a larval host in Central Texas, we could make seeds or plants available for people with shady patios and balconies.”