Due to the importance of Asclepias syriaca (common milkweed) to the eastern population of the monarch butterfly (Danaus plexippus), it is usually recommended for planting by federal conservation programs and state monarch recovery plans. However, A. syriaca has long been considered a weed, and is commonly found in roadsides and other disturbed landscapes where it has not been deliberately introduced. We wanted to determine if seeding A. syriaca is necessary for its establishment, or if milkweed populations in the surrounding landscape could spread into the plantings. In this study, we examined the density of A. syriaca in relation to the seeding rate and surrounding land cover in the Conservation Reserve Program’s Pollinator Habitat Initiative (CP-42) plantings. In June and July of 2018 and 2019, we surveyed 45 CP-42 plantings for milkweed density. In ArcGIS, we created a 1 km buffer around each site and calculated the percentage of land within the buffer covered in road, forest, and habitat suitable for A. syriaca. We found a significant positive correlation between A. syriaca density and the rate at which it was seeded. There was no correlation found between A. syriaca density and surrounding land cover categories. Based on these results, we determined that seeding rate is important for establishing higher densities of A. syriaca in CP-42 plantings. At this time, we cannot draw conclusions on the importance of surrounding land cover on A. syriaca density. By understanding the density of A. syriaca in CP-42 plantings, we can adapt policy and management to efficiently provide crucial habitat for monarchs and other pollinators
