King County, WA Landscaping Rules: Native Plants (2026)
Key Facts
- Core rule
- K.C.C. § 21A.16.085(F)
- Applies to
- new landscape areas, all new development
- Incentive
- up to 25% fewer trees/shrubs (§ 21A.16.100.F)
- Not covered
- Seattle, Bellevue, Kent, Renton, 27+ other cities
Summary
Unincorporated King County requires new landscaping to use native or climate-adapted plants and encourages keeping existing natural vegetation in place rather than ripping it out for turf.
Plants selected shall be natives, or other plants adapted to the climatic, geologic and topographical conditions of the site. Preservation of existing noninvasive vegetation is encouraged.
G. Landscape areas shall incorporate low-impact development best management practices to the maximum extent practical, consistent with the bioretention design standards of the Surface Water Design Manual, including soil mix and plant selection, and shall also meet the standards of this chapter for types of plants used and their spacing and density. (Ord. 19881 § 258, 2024: Ord. 18257 § 22, 2016: Ord. 11210 § 9, 1994).
21A.16.090 Landscaping - additional standards for required landscape areas. In addition to the general standards of K.C.C. 21A.16.085, landscape areas required pursuant to K.C.C. 21A.16.050 through .080 shall conform to the following standards:
A. All plants shall conform to American Association of Nurserymen (AAN) grades and standards as published in the "American Standard for Nursery Stock" manual, provided that existing healthy vegetation used to augment new plantings shall not be required to meet the standards of this manual;
B. Single-stemmed trees required pursuant to this chapter shall at the time of planting conform to the following standards:
1. In parking area landscaping and in street rights-of-way:
a. Deciduous trees shall have a minimum caliper of 1.75 inches and a height of 10 feet, and
Full Breakdown
Under King County Code § 21A.16.085(F), every new landscape area on a development site must be planted with natives, or with other species suited to the site's climate, geology, and topography, and the county explicitly encourages preserving existing noninvasive vegetation instead of clearing it. A companion incentive at § 21A.16.100(F) lets projects cut required perimeter and parking-lot trees and shrubs by up to 25 percent when they plant species typical of the Puget Sound Basin. These rules apply to new development landscaping countywide in unincorporated King County; Seattle, Bellevue, Kent, Renton, Federal Way, and the county's other 27-plus incorporated cities enforce their own separate landscaping codes.
Violations & Fines
Landscaping is checked at permit review and before occupancy: a certified plan and installation affidavit are required (§ 21A.16.115), and unfinished work needs a financial guarantee before a certificate of occupancy issues (§ 21A.16.190). Noncompliant sites face code enforcement.
Frequently Asked Questions
Does King County require native plants in landscaping?
Can native landscaping reduce other requirements?
Does this rule cover Seattle or Bellevue?
Sources & Official References
Other rules in King County
Compare King County to another location·View the Washington landscaping rules overview
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