Kirkland, WA Landscaping Rules: Native Plants (2026)

41, Supplemental Plantings, any part of a developed lot that is not built on, not used for vehicle circulation, and not otherwise committed to a specific use must be landscaped to City standards. The code sets a hard coverage benchmark: living plant material must cover 80 percent of the area within two years of planting, and if the chosen material does not spread over time the applicant must replant the whole area immediately. Anything not covered by living plants has to be covered with nonliving groundcover such as mulch.

The code then states a clear preference for native species, pointing applicants to the Kirkland Native Tree/Plant Lists maintained by the Planning and Building Department. Beyond groundcover, the standard requires one tree for every 1,000 square feet of landscaped area, with deciduous trees planted at a minimum two-inch caliper and coniferous trees at a minimum six feet in height at planting. Larger or taller building facades subject to Process I, IIA, or IIB review can trigger additional vegetation requirements for visual screening. 30 tree retention plans give the Planning Official authority to weight retained native trees and vegetation heavily when judging a project's compliance, and native plant material is again the default choice under the mitigation and buffer-restoration standards found elsewhere in Chapter 95 and Chapter 90. 40(3).