Effective Establishment of Native Grasses on Roadsides

Grass is an important component of the roadside landscape. For safety reasons it is the preferred vegetation within the clear zone, and it is a primary means for controlling slope erosion. Currently New England Departments of Transportation (DOT')s and other highway departments in New England rely on traditional cool‐season turf grasses for roadside use. Seed of these grasses is readily available and the grasses are easily established using hydro‐seeding. However, commercial varieties of these grasses are descended from populations native to Europe, and most botanists consider these grasses to be introduced species. Some non-native cool season grasses are now considered to be invasive species. In 1995 the National Environmental Policy Act mandated that native species should be used in all federally funded landscaping projects to the maximum extent practicable. In 1999 Executive Order 13112 required all federal agencies to prevent the introduction or planting of invasive species and prohibited their use in federally funded landscaping projects. Since this Executive Order went into effect budgetary constraints may have affected implementation. Regardless, there is a movement toward using native species in roadside environments nationally. Native plants tend to be less demanding, establish in the landscape more easily, have reduced pests issues, and help to create a more native and regional appearance to roadsides. Native plants including native grasses are out competed by non-native species especially invasive species. One of the leading reasons for use of natives vs. non-native is maintaining regional bio-diversity. Non-native and invasive plants occupy and compete for space with native species. Regionally, non-native and invasive species continue to diminish native biodiversity as they spread and crowd out natives. The U. S. Department of Transportation bulletin "Roadside Use of Native Plants" lists 32 grasses and grass‐like species for use in New England. Of these, 19 are obligate wetland species and thus not suited to use in most roadside plantings. The remaining 13 species includes some which are commonly found on roadsides, such as purple lovegrass (Eragrostis spectabilis) and little bluestem (Schizachyrium scoparium) as well as commercially important species such switchgrass (Panicum virgatum). Preliminary results from the Rhode Island Department of Transportation (RIDOT)‐funded research project "Evaluation of Native Grasses for Highway Slope Stabilization and Salt Tolerance" show that some of these species are very deep‐rooted and would be superior to the turfgrasses currently used for slope stabilization. However, native grass seed is quite expensive and most of the species listed as native to Rhode Island are challenging to establish from seed. Transplants establish more readily but the amount of manual labor required for transplanting makes transplants prohibitive for general use by RIDOT. Establishment of native grass plantings from seed is further complicated because most of the species listed are warm season grasses. Warm season grasses germinate in the spring and summer and grow most actively in the summer. Seedlings are slow to establish and the growing point is located at the soil surface, making the seedlings very susceptible to drying out during establishment. The most common weed species on our roadsides is crabgrass (Digitaria ischaemum) which is an introduced warm‐season annual grass. Crabgrass germinates in early summer like the native warm‐season grasses, but crabgrass seedlings are very vigorous and can quickly crowd out the weaker seedlings of perennial native grasses. In contrast, the turfgrasses currently used on roadsides are cool‐season grasses. They can be established in the fall, avoiding competition with germinating crabgrass. In the spring selective herbicides will prevent the germination of crabgrass without inhibiting germination and establishment of cool‐season grasses. Commercial varieties generally have good seedling vigor and minimal dormancy, and less expensive seed permits the use of higher seeding rates. Overall it is more convenient, simpler and less expensive to establish traditional turfgrass species on roadsides than to use native grass species. However, once native species are established they may actually do a better job of preventing erosion and require less maintenance than the traditional turfgrasses. In addition, using native grasses conforms with federal policy and avoids the problem of planting large areas to introduced species which may become invasive. To increase use of native grasses it is necessary to learn how to successfully and economically establish these grasses from seed under roadside conditions. Further, research may need to examine the use of native forbs and wildflowers in combination with native grasses as a means of filling the niches that native grasses may not fill. Utilizing native grasses in combination with native forbs and wildflowers would improve the biodiversity and potential success of developed native roadside mixes and aid in establishing better cover that would be more resistant to weed, introduced, and invasive introduction. Much work has been done on establishment of native grasses in prairie restorations and for use as pasture. However, the research has focused on the species and ecotypes of the Great Plains and the Midwestern prairie, rather than on the ecotypes of the East Coast. Climate and soil conditions are different in New England than in the Midwest and West, and roadsides are very different from the agricultural lands often used for prairie restorations and pasture. This research will result in an improved understanding of how to establish New England native grasses from seed. The primary deliverable will be a manual for use by highway department employees and contractors with detailed instructions on how and when to establish native grasses from seed, including recommended mixes for different sites and conditions. This will enable DOT's to economically increase the use of native species, improving slope stabilization, reducing the need to mow slopes, and enhancing compliance with federal mandates.


  • English


  • Status: Active
  • Contract Numbers:

    NETC 09-2

  • Sponsor Organizations:

    New England Transportation Consortium (NETC)

    University of Vermont
    Burlington, VT  USA  05405
  • Project Managers:

    Hanaway-Corrente, Amanda

  • Performing Organizations:

    University of Connecticut, Storrs

    Storrs, CT  USA  06268-5202
  • Principal Investigators:

    Kuzovkina, Julia

  • Start Date: 20130901
  • Actual Completion Date: 20160228
  • Source Data: RiP Project 35796

Subject/Index Terms

Filing Info

  • Accession Number: 01503463
  • Record Type: Research project
  • Source Agency: New England Transportation Consortium (NETC)
  • Contract Numbers: NETC 09-2
  • Files: UTC, RiP
  • Created Date: Jan 8 2014 1:01AM