Issaquah, WA Tree Protection: Parkway Planting (2026)
Key Facts
- Deciduous street tree size
- Minimum two-inch caliper at planting
- Conifer street tree size
- Seven feet tall at planting
- Limbing at planting
- Limbed up a minimum of five feet (ANSI Z133-2017)
- Tree pit in a tree well
- 16 square feet minimum; three times the rootball
- Planting strip
- Five feet minimum, sidewalk to back of curb, unless otherwise permitted
- Deviation authority
- The Director, under IMC 18.606.190
Summary
Issaquah requires street trees on every project application that must provide frontage improvements in the right-of-way. Deciduous street trees must be at least two-inch caliper and conifers seven feet tall at planting, limbed up five feet, with a planting strip of at least five feet between sidewalk and curb unless otherwise permitted.
H. All pedestrian facilities must be buffered with trees and shrubs, appropriate in size, scale, planter type, and character to the type of facility or subarea. Landscape adjacent to parking must be hardy and easily traversable such as with pavers to guide pedestrians. Unless otherwise permitted, the width of the planting strip must be a minimum of five feet between the sidewalk and the back of the curb. ... J. Street trees are required for all project applications required to provide frontage improvements in the rights-of-way, unless the Director approves a deviation in accordance with IMC 18.606.190 . Street trees must be a minimum of two-inch caliper for deciduous trees and seven feet tall for conifers at the time of planting. Street trees must be limbed up a minimum of five feet when planted, following the standards provided in ANSI Z133-2017. The minimum tree pit size in a tree well must be 16 square feet and the minimum tree pit must be three times the size of the rootball.
Full Breakdown
Street trees are governed by Issaquah Land Use Code § 18.606.170, Public properties. Paragraph (J) requires street trees for all project applications that must provide frontage improvements in the rights-of-way, unless the Director approves a deviation under IMC 18.606.190. At planting, deciduous street trees must be a minimum of two-inch caliper and conifers seven feet tall. Street trees must be limbed up a minimum of five feet when planted, following ANSI Z133-2017. The minimum tree pit size in a tree well is 16 square feet, and the tree pit must be three times the size of the rootball.
Paragraph (H) buffers pedestrian facilities with trees and shrubs appropriate in size, scale, planter type, and character, and sets the planting strip width at a minimum of five feet between the sidewalk and the back of the curb unless otherwise permitted. Paragraph (I) requires trees planted under overhead utility wires to be selected per the approved tree list so they will not grow up to interfere with the wires.
Selection and approval run through the City. Under paragraph (B), the City keeps a preferred tree list from which developers select; a tree on public property that is not on the list requires City approval, and the list is available at the permit center. Paragraph (F) requires City permission before any plant is planted or removed from City property or public right-of-way. Section 18.606.040(H)(7) requires street trees to be sized according to Chapter 18.812 IMC, Tree Preservation, and the preferred and prohibited tree list.
Planting space is also set in § 18.606.040(L)(2): required tree planting areas must be a minimum width of five feet with a minimum soil volume of 1,200 CF, and tree wells must be a minimum of 24 square feet of open area, though continuous landscape beds or lawns are considered preferable. The 16 and 24 square foot figures are printed in different sections.
Maintenance of landscape areas on City right-of-way, including irrigation systems and ornamental plantings, is the responsibility of the abutting property owner unless the City has accepted it, and any tree removal requires City approval (paragraph (E)).
Violations & Fines
Violations of Chapter 18.606 are subject to the enforcement and penalty provisions of Chapters 18.108 and 18.812 IMC (§ 18.606.180(A)), and § 18.108.010 deems Land Use Code violations civil violations enforced under Chapter 8.45 IMC. Planting or removing any plant on City property or public right-of-way without City permission contravenes § 18.606.170(F), and tree removal on right-of-way requires approval under IMC 18.812.050.
Frequently Asked Questions
When does Issaquah require street trees?
How big must a street tree be when planted?
Who maintains the planting strip and street trees?
Sources & Official References
Other rules in Issaquah
Compare Issaquah to another location·View the Washington tree protection overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.
Parkway Planting in Nearby Cities
How other cities in King County handle parkway planting.