Establishing North American prairie vegetation in urban parks in northern England: Part 1. Effect of sowing season, sowing rate and soil type

This study investigated the establishment of 17 species of North American prairie forbs and grasses by field sowing in Sheffield, a city in northern England. The purpose of the work was to see whether it was feasible to use this sown, naturalistic plant community as a more sustainable alternative to traditional herbaceous plantings in urban parks. Key variables in the study were, sowing season (summer and winter), soil type (topsoil, subsoil, and sand mulched topsoil) and sowing rate (0.625, 1.25, and 2.5 g/m 2). All experimental plots were baited with metaldehyde containing pellets to reduce the impact of slug predation. For the sown community as a whole, the highest seedling emergence was recorded on subsoil plots sown in winter, and overall, winter sowing was superior. The lowest emergence was recorded on sand mulched plots sown in summer, although even in this treatment emergence was satisfactory in terms of landscape practice. For individual species, high levels of emergence were dependent upon specific combinations of soil type and sowing season. High seedling densities were recorded: from 64 seedlings/m 2 at the low rate, to 315 seedlings/m 2 at the high rate. The most successful species were: Echinacea pallida, Echinacea purpurea, Monarda fistulosa, Ratibida pinnata, and Solidago rigida. The least successful species were: Coreopsis tripteris, Solidago ohioensis, Sporobolus heterolepis, and Veronicastrum virginicum. Soil type had a significant influence on weed density in the experiment, with sand mulched plots the least weedy, and topsoil the most weedy. The study has shown that given control of mollusc predation during the emergence period, all of the species chosen could be established by sowing in situ in northern England.