Roadway Plantings

Review Benefits of Plantings in the ROW

• Planted medians increase the traffic calming effect afforded by medians. Review Raised Median
• Can incorporate pedestrian amenities such as seating or other furnishings to encourage social and recreational activities, depending on size and maintenance
• Provides an opportunity to actively collect and manage stormwater. Review Median Stormwater Management Practices

Review Key Considerations

Siting and Visibility

• Consider height and width of shrubs, grasses, and perennials at maturity, especially with Raised Plantings. If necessary, keep taller plants towards the interior and use shorter plants along the exterior of plant beds. Choose dwarf species where visibility is a concern
• Maintain clear view corridors to visual resources (i.e., bodies of water, significant landmarks, etc.)
• Allow adequate room for trucks and buses to make necessary turns without damaging plant material
• Consider pedestrian and bicycle circulation

Existing Constraints

• Consider underground utility constraints, as excavation beneath the roadbed will be necessary to provide adequate soil volume and positive drainage. Raised Plantings may allow for plantings where there are conflicts
• Existing trees should be preserved whenever possible; consider installing geometric design treatments around the trees to prevent excavation and change of soil grade. Review Key Considerations: Tree Preservation and Protection
• Roadway plantings may impact street drainage or require catch-basin relocation.
• Consider the collection of stormwater. Review Stormwater Management Practices

Environmental

• Consider environmental and physical stresses plants must withstand, including drought and inundation, sun and shade, heat and cold, wind, pollution, road salt, garbage, vehicular damage, disease and pests, and compaction. Pay close attention to the local microclimate, especially if near the coast or a body of water
• Consider the lifespan and longevity of species, as plant replacement will be difficult and costly

Maintenance

• Safe access to plantings for maintenance workers must be provided; consider how maintenance workers will access the plantings to perform regular maintenance activities, especially watering. This may require a lane closure permit from DOT and should utilize appropriate safety equipment
• Parks maintains roadway plantings covered under the Parks and DOT Greenstreets agreement; Parks is also responsible for plantings located on mapped parkland, such as certain pedestrian malls
• DOT maintains certain roadway plantings installed as part of Vision Zero, step street, priority bus, or priority bike lane projects.
• DEP maintains roadway plantings located within Stormwater Management Practices funded by DEP
• Certain Street Ends are subject to DOT-Parks Street Ends MOUs; these are typically built as part of a Waterfront Access Plan required by the New York City Zoning Resolution
• Plantings in the roadway not maintained by the City require a maintenance agreement with DOT

Typical roadway planting locations include:

• Medians, both curb height (6 to 7 inches) and raised (18 to 24 inches)
• Pedestrian malls, wide medians that typically allow for walking and biking and may also support other amenities like seating, bike parking, wayfinding, etc.
• Triangles, planted areas can be any shape and size, not just a triangle, and typically channelize traffic
• Street ends, areas at the end of a street typically adjacent to a body of water. Plantings, if applicable, must provide access to the area beyond the street end. Street ends are often regulated through a Waterfront Access Plan pursuant to the New York City Zoning Resolution

Review Raised Median in the Geometry chapter for geometric design guidance; all medians must include a paved area, free of vegetation or obstructions, for pedestrians to safely cross at the intersection

Review DOT’s Planted Raised Median Design Guidelines for further information

Review design guidance for Tree Bed when planting trees

Review Planted Stormwater Management Practices, specifically Median Stormwater Management Practices where appropriate

• Design details should be determined on a site-specific basis with Parks, DOT, and, if applicable, DEP
• In-Ground Plantings are preferred. Raised Plantings may be considered in higher traffic areas to prevent vehicular incursion into planted areas; design to the minimum height necessary to accommodate necessary soil depth. Refer to Container Plantings if applicable

Size and Drainage Requirements

• Planted medians should be a minimum of 7 feet wide to allow for 6 feet of planting space with a 6-inch-wide curb on either side. Exceptions may be approved by DOT and Parks on a case-by-case basis. Where conditions allow, a buffer around the perimeter of the planting bed is preferred to allow for maintenance access
• If walking or biking is provided, planting areas should be designed to accommodate necessary circulation; paths should be uninterrupted. A minimum of 8 feet must be provided for a pedestrian-only path, 8 feet for a two-way bicycle path, and 12 to 14 feet, depending on the volume of users, for a shared-use path
• Planting beds should be sufficiently wide and deep to provide adequate soil volume for plants: provide at least 18 inches for grass or ground cover, 18 to 24 inches for shrubs, and 18 to 30 inches for trees. The soil depth should also relate to the root ball depth at planting – review Key Considerations: Soils. Exceptions may be approved on a case-by-case basis
• Positive drainage below the planting soil is essential. Any impermeable layers of concrete or asphalt must be removed or appropriately designed weep holes must be included

Planting

• Review the Plant Finder for plants that perform well in the right-of-way. Plant selection must always be made based on site-specific conditions.
• Use drought-tolerant, salt-tolerant species that require little to no pruning or deadheading to maintain their shape, size, vitality, and ornamental interest; review Key Considerations: Plant Selection
• Where conditions allow, medians should be planted with large-growing canopy trees
• Consider the use of a suspended pavement system and Connected Tree Beds
• Tree spacing should be based on the appropriate mature width of the species chosen and must be approved by Parks. Review Siting Guidelines; minimum distance from the curb at the end of the median to the center of the tree trunk is 35 feet
• Where truck and bus traffic is heavy, consider using columnar species to reduce damage to plants
• Consider planting fewer understory species to provide continuity and reduce overall maintenance needs; select plants that will provide year-round ornamental interest
• Space shrubs and other plants to encourage dense, full growth and deter weeds; however, do not overcrowd, which can lead to poor air circulation and encourage the spread of pests and diseases
• In planting areas with trees, consider understory species that will tolerate varying light conditions as tree species mature and provide more shade
• Plants must not protrude into the roadway; plant densely within the bed to discourage weed growth and trampling. In Raised Plantings, plants that cascade over the edge of the wall may be acceptable

Additional Amenities

• Consider the use of tree-bed guards or similar fencing around planting areas to discourage trampling of plant material. In certain areas, more substantial barriers such as guide rail or bollards may be necessary to prevent vehicular access and damage to plantings. All barriers must be reviewed and approved by DOT, and any non-standard barriers will require a maintenance agreement
• Consider how the planting design will function with other elements, such as seating, bike racks, wayfinding, lighting, and artwork