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Kent, WA Invasive Plant Rules: Prohibited Species (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified August 2026

Key Facts

Barred species
WSDA Class A, B, C noxious weeds (Ch. 16-750 WAC)
Applies to
Wetland, stream, habitat, geologic hazard mitigation plantings
Removal plan required
Before planting begins (KCC 11.06.550(C)(12))
Buffer reduction cap
Type F buffer restoration allows 10% or less noxious weeds
Enforcing department
Kent Public Works Department critical area review
Penalty
$500 per violation, $100 minimum if mitigated

Summary

Kent's critical areas code bars any Washington State Department of Agriculture-listed noxious weed from replanting done to compensate for wetland, stream, or habitat impacts. KCC 11.06.550(C)(1) requires every mitigation planting plan reviewed by the city to skip WSDA Class A, B, and C species, and applicants must submit an invasive-plant removal plan before installing any new vegetation.

Use plants native to the Puget lowlands. Use of species outside the Puget lowlands may be permitted when such species are native to the Pacific Northwest ecoregion and have demonstrated resilience to projected climate-related stressors. Plants listed by the Washington State Department of Agriculture as noxious weeds (Chapter 16-750 WAC) shall not be used.

View official code

Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance 4542, passed June 16, 2026).

Full Breakdown

030). 550(C). ' Standard 12 goes further, requiring the mitigation plan to include an invasive-plant removal program naming target species, removal methods, and a timeline, before any new planting occurs. 391 as nonnative vegetation the state Noxious Weed Control Board has classified as Class A, B, or C. Herbicide use to control those weeds is restricted too: standard 11 allows herbicides only if they are approved for aquatic ecosystems by the Washington Department of Ecology and applied by a licensed applicator. 760(D)(3) allows landslide-hazard buffer vegetation 'infested by noxious and invasive weeds' to be replaced with native species only under a department-approved enhancement plan. The Kent public works department reviews and approves every mitigation and monitoring plan before a building or construction permit can issue.

Violations & Fines

Mitigation plans that specify a WSDA-listed noxious weed, or that omit the required invasive-plant removal program, are rejected by the department during critical area review and cannot support permit issuance. Once work has started, code enforcement proceeds under Chapter 1.04 KCC: the hearing examiner may impose a $500 monetary penalty per violation (reducible to no less than $100 if mitigation is requested), with each day a noncompliant planting persists counted as a separate violation.

Frequently Asked Questions

Can I plant blackberries or Scotch broom in a Kent wetland buffer restoration?
No. KCC 11.06.550(C)(1) prohibits using any species the Washington State Department of Agriculture lists as a Class A, B, or C noxious weed in mitigation plantings, and Himalayan blackberry and Scotch broom are both WSDA-listed noxious weeds, so neither can appear in a city-approved planting plan for wetland, stream, or habitat mitigation in Kent.
Does Kent require a plan to remove existing invasive plants before replanting?
Yes. KCC 11.06.550(C)(12) requires every mitigation plan to include an invasive-plant removal program identifying the target species, the removal method, and a timeline, so the department can confirm the site is cleared of competing invasive growth before new native plantings are installed.
What noxious weed threshold applies if I want to shrink a stream buffer in Kent?
KCC 11.06.680(E) allows a Type F stream buffer to be reduced from 150 feet to 112.5 feet only if the restored buffer achieves at least 80 percent native woody cover and no more than 10 percent noxious weeds, verified by the city before the reduction is approved.
Who enforces Kent's noxious weed planting ban and what's the penalty?
The Kent public works department reviews mitigation plans under Chapter 11.06 KCC, and violations are enforced under Chapter 1.04 KCC, where the hearing examiner may impose a $500 penalty per violation, reducible to no less than $100 through the mitigation hearing process, with each day of noncompliance counted separately.

Sources & Official References

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