That would not be my first choice of location for them. Best in a lightly shaded area with adequate soil moisture.....more of an open woodland, woodland verge or streamside plant rather than the dry shade that exists under a WRC. Try the native bleeding hearts (or even the hybrid fernleafs) in that location. They should do quite well.

Yes, in nature you see scattered individuals on the edges of trails and other places where there is freshly disturbed soil, maybe often a little on the dry side - at least at flowering time: streamsides and banks where moisture may run in spring could be typical locations. Robert Nold, Columbines (Timber Press) talks quite a bit about the importance of keeping these (columbines in general) moist. And under A. formosa he mentions a specific form being collected where it was growing on dripping cliffs in the wild.

Wouldn't expect this to like the conditions within the skirt of a Thuja at all. This is one of the toughest common garden situations in this area, with people thinking about what to plant there specifically because it is a hard place for many plants to grow, therefore tending to be empty.

They can take full shade, but they won't do much there. If you want flowers they need at least part sun. I do see them in sites that get pretty dry in summer, where they get about half sun half shade. They could take full sun if they get water.

I never see them under cedars. Woodland edge plant, where they get shaded by trees but aren't directly under them.

Thank you all for the responses - pretty clear that under the cedar is not the right place!

If you're looking for something to plant in that dry/light shade spot, Mahonia nervosa (Cascade Oregon grape) might be a good choice.

This post was edited by OregonGrape on Sun, Feb 24, 13 at 13:00

OregonGrape: Thanks for the suggestion - I was hoping to get some flowers in that area and I guess I will just leave it blank/bare for now.

I'm thinking you might be able to succeed with Cyclamen hederifolium there. Put down a layer of topsoil for them to get started in, being a wetland species the cedars shouldn't mind - as long as the new soil layer isn't real thick or dense.

Another one I would try is Iris foetidissima. Look for var. citrina, with partly light yellow flowers - it is much more effective in bloom.

Milium effusum 'Aureum' might also grow for you there, not a flowering plant but still lovely and colorful.

This post was edited by bboy on Mon, Feb 25, 13 at 20:31

As I mentioned, our native Dicentra formosa will work well under the canopy of WRC's. Another great plant for this situation is Euphorbia robbiea. Flowers not as colorful as the bleeding heart but the plant is evergreen and will grow easily in some of the darkest, driest, least hospitable conditions.

Both of these are colonizers or spreading plants but rampant growth is typically moderated by the dry shade conditions that exist under cedars.

I've attached a link to a very good list of plants suitable for PNW dry shade developed by Richie Steffen, curator of the Elizabeth Miller Garden, sponsor of the Great Plant Picks program.

Here is a link that might be useful: plants for dry shade - PNW

I've grown white Dicentra formosa under Nootka cypress. The spurge, like the iris is a classic for dry shade.

Thank you for all the idea. I'll try out some bleeding hearts in that spot - hopefully they do well there.