You are looking for the native species, Cornus nuttallii. A fair number of area nurseries will carry them, especially those that feature native plants. You should be aware that they are quite prone to dogwood anthracnose, an often fatal fungal affliction that is devastating native stands, particularly those close to urban areas. Should they remain healthy enough or live that long (you, too!!), they could reach 45-50' tall.

An alternate choice might be Cornus 'Eddie's White Wonder', a hybrid of our NW native with the eastern dogwood. With mature size and flower size/shape and bloomtime very similar to our native, it is a much more disease resistant selection.

The hybrid is a superior ornamental anyway.

They're very slow growing, and with any tree the first year or so is often spent growing roots rather than trunk or branches. They like decent soil, with drainage but not all rock; and no hot reflected sun; and regular water while getting established the first few years. You might just need to be patient.

Many moons ago I worked in a Nursery that propagated our native Dogwood. The seed was collected in the fall (before the Starlings found it) The seed was then scrubbed over wire mesh to scarify it, then planted in flats and placed outside to face our winter whatever it may be. The germination rate was excellent. Hope this helps. I also think Eddie's White Wonder is a better choice.

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