Seattle gardener Marty Wingate loves the Pacific Coast iris: it's a native plant, so it doesn't require summer watering, it has a nice grassy look and it thrives in partial shade.
The fall is a great time to divide this iris. It is dormant in the summer, but with the fall rain, it starts to shoot out new growth.
You'll need to use a garden fork to lift the plant up a little; it's not a very upright plant with its leaves tending to sprawl outward. You're looking for pink little nodes that indicate new growth.
Cut this piece as far back as you can get with your garden trimmers.
Plant with stem horizontal, roots heading down in soil, but don’t bury too deeply. You may need to anchor it with a stone.
In a couple weeks, the iris will start to shoot forth new leaves, like this one to the right.
And then, in May, you can expect a lovely yellow flower, one iteration of the Pacific Coast iris.