Howard County, MD Tree Protection: Parkway Planting (2026)

Section 16.124 of the Howard County Code sets the county's landscaping and street tree standards for every subdivision, site development plan, and road-improvement project. Subsection (e), Street Trees and Right-of-Way Plantings, requires a minimum two-and-one-half-inch caliper for every street tree, applied uniformly across every zoning district, and ties the planting specifications to the Howard County Landscape Manual, the technical document the Department of Planning and Zoning maintains and updates by County Council resolution. A developer meets the requirement by planting new stock along internal roads or along existing roads where the county requires road improvements; where mature trees already stand in or adjacent to the right-of-way, the Department can award credit toward the caliper requirement of up to 100 percent for each tree preserved instead of removed and replanted.

Street tree plantings are kept administratively separate from the county's other tree programs: subsection (e)(2) states street trees cannot be counted toward the reforestation or afforestation obligations of the Forest Conservation Program, and they cannot double as the perimeter or parking-lot landscaping required elsewhere in Section 16.124(b). The developer must show the street tree layout on the final subdivision plat or the site development plan, and if the State Highway Administration has jurisdiction over the road, its review applies as well.

Under subsection (f), required landscaping, including street trees, is written into the developer's agreement for the subdivision, and the county holds surety until the planting is installed to the approved plan; the developer must also give the county a one-year guarantee on the plant material before that surety is released. Subsection (g) shifts the ongoing duty to the property: the owner, tenant, and their agents are jointly and severally responsible for keeping required trees in good growing condition and replacing any that die, and no plant material may grow into the road right-of-way in a way that blocks sight distance.