Abstract

We assessed the status of 34 native species plantings along roadsides in Indiana and Illinois and evaluated soil conditions, distance from road, and surrounding landscape cover to determine which factors led to successful long-term establishment of plantings. Cover by seeded native species and native species overall increased with distance from road and decreased with increasing soil nitrate and phosphorous. Number of native species and seeded native species increased with distance from road and greater seed mix diversity. In contrast, richness of non-native, non-seeded species was greater at shorter distances from road. Across all sites, 84 of the 150 native species seeded at sites were never observed in our surveys, but 28 native species were observed at more than half of the sites in which they were seeded. Our results suggest that native plantings can persist on roadsides for several years after planting, but that specific site-level factors increase the likelihood of long-term success.

Keywords

environmental quality, invasive plants, prairie, roadsides, seeding, soil quality, vascular plants

Report Number

FHWA/IN/JTRP-2025/14

SPR Number

4810

Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette, Indiana

Date of Version

2025

DOI

10.5703/1288284317878

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