Residents use landscaping to help water quality in lakes

July 19, 2011

By Caleb Heeringa

Sammamish resident Gayle Twelves points out some key features of her pond and native-plant landscaping. Photo by Christopher Huber

The second in a series that will examine what people in the city are doing to become more ecologically friendly.

Aside from a few patches of well-manicured lawn, the plants and shrubs that inhabit Gail Twelves’ back yard are not unlike those that you would see when wandering through the woods that covered the Sammamish Plateau centuries ago.

With cedar trees towering overhead, Oregon Grape and other native shrubs intermingle with the occasional stand of sword ferns below.

For Twelves, who lives in the Loree Estates neighborhood with her husband Scott Hamilton, the native flora has numerous environmental benefits. It doesn’t require herbicides or pesticides that can be harmful to the surrounding ecosystem. And since it evolved in Pacific Northwest it acts as a veritable sponge compared to non-native plants when it comes to the several feet of rainfall the area gets every year. That means less storm water running off into the environmentally sensitive lakes and streams in the city.

“Sammamish has a lot at stake, with three major lakes and more than 11 miles of shoreline,” Twelves said. “That’s three lakes that really depend on us doing this right.”

Twelves is one of many Sammamish homeowners who are keeping the environment in mind when landscaping and gardening. And while some measures are big-ticket items – installing green or living roofs or rain gardens that gather and filter run-off before it goes into neighboring streams, for example – some fixes are cheap, simple and effective.

Liza Burke, community relations manager with organic gardening advocacy group Seattle Tilth, suggests taking a self-guided tour through their garden at Pickering Barn in Issaquah. The garden is a grab bag of organic gardening tips – from which vegetables grow well in the damp Pacific Northwest environment to how to set up a rain garden or compost pile. The organization also occasionally offers classes around the Seattle area.

Sheri Henshaw, a garden educator for the organization, said the easiest thing a gardener can do is to use organic compost instead of store-bought fertilizer full of phosphorus or nitrogen. If you are using fertilizer, make sure it is phosphorus free – King County recently forbade homeowners from using phosphorus fertilizer except when a lawn or sod is being installed for the first time or when certified tests show the soil is low in phosphorus.

While the focus is often on fish and aquatic life in lakes and streams, Twelves said it’s a matter of human and pet health as well.

“We let our dog out on the lawn,” she said. “We don’t want him out getting those chemicals on his paws and licking them.”

Trees are also key to maintaining a healthy ecosystem and getting your yard closer to the state it was in prior to development. As far as water retention goes, few things are better than the root system of an adult tree.

“I hate to see people cutting down mature trees,” Twelves said. “People don’t think of the job that a tree is doing for them.”

When it comes to amending soils, Henshaw said it is “buyer beware” when it comes to buying topsoil or compost or any other gardening products.

“Be careful who you’re buying top soil from,” she said. “Some places resell old top soil, so you don’t know where it’s coming from … or what kinds of chemicals may be in it.”

Homeowners that are willing enough to truck in topsoil for their gardens may also take the next step and install a rain garden – essentially installing some sort of fill material that acts as a natural drain field that retains and filters runoff. Henshaw said that though most of the rain gardens being installed in the Puget Sound are going into larger commercial or public projects, it’s nothing that can’t be accomplished by a residential homeowner who does their homework. Seattle is currently offering citizens in the Ballard neighborhood rebates on the installation of some rain gardens.

“You have to be careful that you don’t flood your neighbor’s basement, but it’s a simple process,” she said.

Washington State University has a handbook that will walk a homeowner through the rain garden installation process. It can be found at:

Twelves said her organic garden is low maintenance and high-impact when it comes to keeping the city’s environment thriving, and the switch from a traditional garden isn’t so drastic.

“People think it’s as hard as switching from being an omnivore to vegan or something, but it’s really not,” Twelves said.

Water conservation tips for gardeners and landscapers

  • Add compost to your soils.
  • Plant native or drought-tolerant plants in your garden.
  • Water lawns deeply, but infrequently. One inch a week during the summer is sufficient.
  • Water early in the morning or late in the evening. A lot of water applied during the heat of the day evaporates and is wasted.
  • Arrange sprinklers so they’re hitting lawn, not pavement.
  • Each spring, inspect all hoses and irrigation tubes for leaks.
Source: Sammamish Plateau Water and Sewer District

So you want to build a rain garden

Sammamish residents interested in installing a rain garden on their property can get a walkthrough from an expert at a free class from 9:30 a.m. to 3:30 p.m. Friday, July 29 at Marenakos Rock Center, 30250 S.E. High Point Way in Preston. For more information and to RSVP, email


Reporter Caleb Heeringa can be reached at 392-6434. ext. 247, or

Bookmark and Share
Other Stories of Interest: , , ,


One Response to “Residents use landscaping to help water quality in lakes”

  1. Kitsap Connection » July 21, 2011 on July 21st, 2011 6:50 am

    […] Residents use landscaping to help water quality in lakes A More Efficient Energy Star […]

Got something to say?

Before you comment, please note:

  • These comments are moderated.
  • Comments should be relevant to the topic at hand and contribute to its discussion.
  • Personal attacks and/or excessive profanity will not be tolerated and such comments will not be approved.
  • This is not your personal chat room or forum, so please stay on topic.