St. Louis County, MO Tree Protection: Parkway Planting (2026)

Section 1005.340 of the St. Louis County Subdivision Ordinance sets the landscaping standard that every new subdivision plat must meet. Before the record plat goes in, the developer submits a landscape plan to the Department of Planning showing the types, sizes and locations of all proposed and existing plantings. That review excludes the part of each residential lot behind the setback line, and the developer guarantees the installation of the planned landscaping by escrow agreement. A large lot subdivision needs no landscape plan at all.

The street tree count depends on the plat. A single-family subdivision needs at least one tree per lot, and a corner lot with frontage on two streets needs one tree for each street. Common land, multiple-family subdivisions and nonresidential subdivisions need one tree for every 50 feet of street frontage, so 500 feet of frontage means 10 trees. Each tree must be at least 1½ inches in caliper. Hardwood and softwood varieties both count, following the current text, but a hardwood must come from the acceptable species list that the Department of Planning maintains. Within each plat, no more than 40 percent of the trees can be one species, which caps a 40-tree plat at 16 of any single species.

Placement is in front of the setback line and outside the street right-of-way, unless a variance under Section 1005.380 allows right-of-way planting. New trees stay at least 3 feet from any curb and at least 10 feet from street inlets and manholes. A tree placed in the right-of-way by variance must be at least 25 feet from street lights. At intersections, no tree can stand inside the triangle formed by the pavement lines and a line connecting two points on the pavement edge 54 feet from where the projected street pavements meet.

A developer can skip the street trees by getting an alternate landscape plan approved, with trees suited in number and species to the area in front of the setback line. Street trees are not required in large lot subdivisions, or in Non-Urban District density-development lots with frontage of 150 feet or more. Subdivision entrance structures or plantings need approval from the Department of Transportation and Public Works, which can also require sodding or other ground cover for erosion control. The Department of Planning can require underbrush clearing, sodding and seeding in common land that has been altered. The section was last amended by Ord. No. 29297 on April 22, 2025.