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Certification Criteria & Checklist

You are invited to display your commitment to water-smart landscaping and your appreciation of our natural and cultural heritage by certifying your garden as a Heritage Garden. Use the information provided on this website to help you determine if your garden has what it takes. If you are feeling overwhelmed or a bit confused, ask your Heritage Garden Representative for guidance early in the process. We want you to succeed. A successful Heritage Garden is a win for all and the birds, bees and butterflies will thank you. Use the certification checklist to document relevant features of your garden. We will use this information in conjunction with a visit to your property to evaluate your garden for certification. 

If you would like a certified garden, be sure to

stick to your plant list and planting plan!

Making substitutions could put you outside certification criteria.

If you need to change plant species,

check with your Heritage Garden Representative first.

BasiRequirements of a Heritage Garden

Plant Species

Your garden must have at least five different species of plants. A more diverse plant population will support more animal species, resulting in greater biodiversity. At least two of these five species must be of value to wildlife. At least one of these five must have cultural or historic significance.

Plant Population

For the total population of plants in your garden, 75% or more must be native to Washington State. You will find that once you meet this goal, you have likely achieved the plant species requirements above.

Next is to evaluate your garden for achieving sustainability requirements, especially water conservation. The Heritage Garden Program was designed to limit the need for supplemental irrigation in the arid regions of eastern Washington (i.e., the Columbia Plateau ecoregion) so is based on natural precipitation of around 10" annually. Therefore, for the total population of plants in your garden, 30% or more must require less than 10" water annually. Once established, these plants will not require supplemental irrigation. Additionally, no more that 10% of the plants in your garden should require more than 30" of water annually. This latter parameter allows your garden to have a bit more diversity without being too dependent on supplemental irrigation.

The Heritage Garden Program has grown, extending west into the Eastern Cascades Slopes & Foothills ecoregion. If your garden location is in this region and precipitation is significantly greater than 10" annually, some adjustments to these criteria may be in order. Contact your Heritage Garden Representative to discuss.

Geologic Features


To recognize Washington's dramatic history of layer upon layer of basalt flows followed by massive floods, your garden must display at least one example of basalt or a rock from the ice-age floods such as an erratic or rock rolled by the flood waters.


With the Heritage Garden Program moving west and climbing into the Cascades, some adjustments may be in order for defining geologic features in these areas. "The geologic history of the North Cascade Range is a complicated puzzle that records over 400 million years of various rocks and terranes..." (Visit North Cascades by Washington States DNR to learn more.) If basalt rock or ice-age flood debris does not represent your geologic history, educate us. Tell your Heritage Garden Representative about the native rock that you would like to use as your geologic feature. The goals are to be representative of your area and to not be unnecessarily hauling in rock over long distances.

Weed Control

Finally, getting and keeping weeds under control is essential as is not allowing plant species listed on Washington's Noxious Weed List to establish themselves. 


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