Landscape, Buffers, and Open Space
Summary
Zoning ordinances require planted areas along streets and lot lines, landscaped islands inside parking lots, buffers and screening where different uses meet, and open space on the lot. These requirements take site area and set fence, wall, and planting details, so count them in the site plan alongside setbacks and parking.
Cols
Scope
- Landscape, buffer, and open space requirements are set by each local ordinance and landscape manual. Always verify the municipal code's definitions and the current zoning for the project parcel
- Covers the common requirement types: street and perimeter planting, parking lot interior landscaping, buffers and screening between uses, and required open space
- Stormwater and impervious surface limits are related and appear in the site drainage and lot coverage notes
Terminology
- Perimeter landscaping (street buffer): a planted strip along a street or lot line
- Interior landscaping: planted islands and strips inside a parking lot
- Landscape island: a planted area within a parking lot, often with a tree
- Buffer yard: a planted or fenced strip separating different uses, such as commercial from residential
- Screening: a fence, wall, or dense planting that hides a use, such as service areas
- Caliper: the trunk diameter of a nursery tree, measured at a set height
- Open space: area on the lot kept free of buildings, often required as a percentage or per unit
- Canopy cover: the share of the site shaded by tree crowns at maturity
- Landscape manual: an adopted guide of approved plants, soil volumes, and details
- Double counting: using one area to satisfy more than one requirement, which many ordinances forbid
Requirements
Parking lot landscaping
- Thresholds: some ordinances apply interior landscaping only to larger lots; one applies it to parking areas of 50 spaces or more
- Trees: one code requires a tree of at least a 3 in. caliper per eight spaces, placed in interior islands distributed through the lot
- Island placement: one code puts an island at each end of a parking row, for rows not adjacent to the perimeter
- Island size: one code sets islands at least 100 sq ft with a narrow dimension of at least 5 ft
- Separation: interior landscaping is kept apart from perimeter landscaping, and perimeter buffers and setbacks do not count toward interior landscaping requirements
Buffers and screening
- Perimeter buffers: required where different uses meet, with width scaled to the intensity of the use
- Reductions: one code requires a 25 ft landscape buffer where nonresidential areas adjoin residential land and allows it to be reduced to 5 ft where an 8 ft masonry wall separates it from the residential area
- Screening: service areas, loading docks, dumpsters, and mechanical equipment are screened by walls, fences, or plantings of a stated height
Open space
- Ordinances may require open or common space as a percentage of the lot or per dwelling unit, especially in multifamily and planned developments
- Open space definitions say what counts: landscaped yards, plazas, roof terraces, and stormwater areas, each with its own limits
- Open space can overlap with required yards, landscape areas, or stormwater treatment only if the code allows
Worked examples
Parking lot trees
An illustrative ordinance with one 3 in. caliper tree per eight spaces and islands of 100 sq ft minimum.
| Step | Calculation | Result |
|---|---|---|
| Spaces | 84 | From the parking calculation |
| Trees | 84 ÷ 8 | 10.5, round up to 11 trees |
| Island area for trees | 11 × 100 sq ft | 1,100 sq ft minimum, if one tree per island |
| Effect on parking layout | Islands replace stalls at row ends | Plan for end islands to avoid losing stalls |
Buffer with a wall
A commercial lot adjoins a residential district along a 100 ft line. The buffer is 25 ft wide, reducible to 5 ft with an 8 ft masonry wall.
| Case | Calculation | Land taken |
|---|---|---|
| Planted buffer | 100 × 25 | 2,500 sq ft |
| Wall with reduced buffer | 100 × 5 | 500 sq ft |
| Difference | 2,500 − 500 | 2,000 sq ft saved for the program |
| Trade-off | Cost of 100 ft of 8 ft masonry wall | Compare with the land value saved |
Open space
A 20,000 sq ft multifamily lot requires 25 percent open space.
| Step | Calculation | Result |
|---|---|---|
| Required open space | 20,000 × 0.25 | 5,000 sq ft |
| Counted | Courtyard 2,500 sq ft + roof terrace 1,000 sq ft | 3,500 sq ft |
| Shortfall | 5,000 − 3,500 | 1,500 sq ft; add ground-level open space or use a different count method |
Coordination
- Landscape architect: plant selection, soil volume, and irrigation come from the landscape manual
- Civil engineer: islands, swales, and rain gardens can double as stormwater treatment where the ordinance allows
- Utilities: trees and utility lines conflict; coordinate with easements and overhead lines
- Lighting: parking lot lighting and tree canopy interact; coordinate fixture and tree locations
- Fire and access: screening walls and plantings cannot block fire department access or visibility at driveways
- Maintenance: ordinances often require maintenance, replacement of dead plants, and sometimes a bond
Common issues
- Landscaping counted twice: perimeter buffer area used to satisfy interior islands
- Island too small: trees die in narrow islands; the minimum dimensions matter
- Tree conflicts with lighting or utilities: found late in the plan
- Buffer lost to setbacks: buffers and yards overlap; the code states which governs
- Wall height limits: screening walls near the street or sight triangles have height limits
- Open space definitions: areas dominated by paving or parking usually do not count
Standards
- Local landscape manual: plant lists, caliper, soil volumes
- Local zoning ordinance: buffer and island dimensions
Sources
- City of Kent, OH: landscaping, buffering, and screening, https://codelibrary.amlegal.com/codes/kent/latest/kent_oh/0-0-0-37175
- City of Gonzales, TX: landscaping and buffer requirements, https://www.zoneomics.com/code/gonzales-TX/chapter_6