Kitaibelia vitifolia (Cedar Cup/Chalice Flower)
I grew this in my garden for at least five years before I knew what it was. It was mislabeled when I purchased it, and as hard as I tried, I had no success in identifying it, so I just referred to it as the "mystery plant" and labeled the seeds the same way. The mystery solved, due to my persistent and diligent sleuthing. This hardy, showy perennial is Kitaibelia vitifolia, also known as Cedar Cup or Chalice Flower, as well as Yugoslavian Hibiscus, although it is not a Hibiscus. This shrub-like perennial grows to at least five feet tall in my garden (see photo below), with large palmate leaves, and it is smothered in large white, chalice-shaped flowers (with absolutely no trace of pink or any other color) all summer long. It likes full sun, although mine receives quite a bit of shade each day and doesn't seem to be bothered by that in the least. Though not a requirement, I often cut mine back in late fall just to keep the garden tidy. This plant is a rarity in gardens - I've never seen it in anyone's garden but mine. It's a spectacular perennial and one that needs to be grown more often. Full sun/partial shade in Zones 5-8. Quarts.