Questions: Can we use local native plants for roadside revegetation? What cultural methods help enhance the process?
Location: Trans Canada Highway, Terra Nova National Park, Newfoundland.
Objectives: To (1) test stratification requirements for seed germination, (2) determine if germination, survival and growth of seedlings and stem cuttings of selected plants can be increased by mulching treatments and (3) identify native plants and cultural treatments useful for revegetation.
Methods: We tested seed germination of Kalmia angustifolia, Iris versicolor, Juncus effusus, Eriophorum vaginatum, Clintonia borealis and Cornus canadensis in a greenhouse experiment. We conducted field experiments of roadside revegetation using seeds of K. angustifolia, I. versicolor, J. effusus and E. vaginatum, as well as seedlings of I. versicolor and rooted stem cuttings of Emptrum nigrum and Juniperus communis after hay-mat mulch and organic matter mulch application.
Results: Stratified seeds of K. angustifolia, I. versicolor, J. effusus and E. vaginatum germinated successfully in the greenhouse, whereas C. borealis and C. canadensis seeds did not. Along roadsides, only I. versicolor seeds germinated. Iris versicolor cover increased significantly in organic matter mulch compared to haymat mulch and control. Transplanted I. versicolor seedlings had high survival in all treatments but growth was reduced in organic matter mulch. Survival and growth of stem cuttings of E. nigrum and J. communis were significantly increased on hay-mat mulch.
Application: Rooted stem cuttings of E. nigrum and J. communis planted on haymat mulch can be used as a practical method of roadside revegetation. These shrubs have low structure, are evergreen, and exhibit stresstolerance properties, which make them ideal species for roadside revegetation. They are also nonpalatable to wildlife. Roadside ditches can be revegetated by seeds or seedlings of I. versicolor. Robust roots and rhizomes of this plant may provide soil stability and dark green leaves and attractive flowers create aesthetically pleasing vegetation cover.