Old Field Vegetation for Low Maintenance Highway Rights-of-Way

Nancy P. Cain

This paper documents research on old field or aster/goldenrod communities suitable for integrated vegetation management (IVM) of low maintenance highway rights-of-way (ROW) in Ontario. Field observation has identified twenty species that are found on highway ROW throughout the province, including Canada goldenrod, grass-leaved goldenrod, New England aster, tall white aster, flat-topped aster and heath aster. The literature indicates that a number of these aster and goldenrod species have allelopathic effects on herbaceous and woody species. This quality, the vigorous dense growth habit of many species and the underground rhizomes make these species highly suitable for highway ROW where control of noxious weeds, brush and erosion are major concerns. Options for using old field vegetation on roadsides include managing existing stands and seeding following construction. In many parts of the province, asters and goldenrods establish naturally providing solid or mixed stands of asters and goldenrods. These areas can be incorporated into IVM programs by identifying these areas and fostering their growth through selective maintenance programs. Aster/goldenrod seed mixtures were developed for Ontario conditions that could be used to establish old field vegetation on roadsides following construction. Seed costs ranged from $1,700 to $4,400 CDN per hectare ($500 to $1300 US per acre). Field experiments found that one to three years are required to establish plants and that a nurse crop is required to stabilize the seeding area while these plants develop.

Keywords: Roadside vegetation, integrated vegetation management, Solidago spp., Aster spp., seeding, allelopathy