I asked the Seattle City Arborist to comment on my original post on city regulations, and apparently I got a few things wrong! Mea culpa. The city does NOT in fact own the parking strip (or planting strip, as they call it), the homeowner does, with an easement for use by the city. There are a number of regulations about height and materials, quoted below, along with the arborist’s contact info in case you have further questions.
"Thanks for your interest in planting strip gardening and sharing information with the general public. I am attaching a Client Assistance Memo (CAM) that discusses planting strip regulations. A list of CAM's published by SDOT is located on the web. Scroll down to"Urban Forestry" for a list of documents published through our division, including planting strips. It sounds like you found the list of suggested plants on the web (the link is found under the "What's Happening" section). The list is currently being updated. Although the list may not be exhaustive, and gardeners are encouraged to be creative, they do need to follow some parameters. Plants grown within the area equal to or less than 30 feet from an intersection may not exceed 24" (2-feet) in height at maturity. This is so that visibility is adequately maintained. (cars and pedestrians visible to each other). When a planting strip is 5-feet wide, or less, plants may not exceed 36" (3-feet) in height at maturity. This is to help assure pedestrian safety/visibility as well as to maintain pedestrian walkways and the roadway clear of overgrowth which may impede travel on the right-of-way. With wider strips, it is possible to put in scattered, taller plants, if planted in the middle of the strip. There are also regulations about "hardscape" - which may include planting beds in the strip. Raised beds may be constructed from timber but rocks or bricks that are easily moved (read here "picked up and thrown") are not allowed. Permits are required for raised beds. Permits are also required to plant, prune or remove trees. Concerning food gardening, while there are no regulations prohibiting it, SDOT does not recommend growing food in planting strips because of safety concerns. The concerns include the proximity of gardening activity to roadways/traffic and unanswered questions regarding soils and contaminants. I would, at a minimum, recommend a comprehensive soil test before considering food gardening in planting strips. One more thing, I work with the traffic circle stewards and just recently initiated a LIST SERV as a means of communication for that group of gardeners. I've included information about signing up." Linden L. Mead, Certified Arborist Seattle Department of Transportation Urban Forestry P.O. Box 34996 Seattle, WA 98124-4996 206-684-5008 email@example.com Hoo boy, can o' worms. Does anyone get a soil test before putting in food plants on the street? I sure didn't think to! Maybe I need to get the next post up soon, on raised beds and soil improvement!