According to the Washington State Nursery & Landscape Association, the city of Seattle announced a list of proposed high efficiency building code changes, entitled Green Code Provisions, which addresses areas, such as: Water Conservation; Material Conservation; Sustainable Transportation; Healthy Landscapes and Misc. Requirements.Of particular importance, the Invasive Species and Native Vegetation (Regional Plan) draft provision is as follows:

Who It Applies To: For all new vegetated landscapes, or those being replaced.
Requirements:
• Existing invasive plant species shall be removed and no invasive species planted.
• 75% of all new plantings will be native to Western Washington.
• A vegetation plan must be submitted for review.
• Existing native plants shall be protected whenever possible.
View the draft Green Code Provision: http://www.wsnla.org/uploads/documents/122.pdf.

For more information:
www.seattle.gov/DPD/Codes/GreenCodeProvisions/Overview/default.asp