I dug so much of it up that only a few little sprigs were left, but I let them grow so I could show you the flowers and here they are. They were small and took a long time to grow and only flowered in early Sept. . Looks like the Saponaria. The phlox also flowered earlier this year. Time to pull up the rest of the Saponaria. This post was edited by olreader on Sun, Sep 28, 14 at 20:18

There could be any number of reasons to explain the problem--poor soil, insufficient water, predators. Lots of astilbes have thrived where I am in your zone so I'm guessing soil is probably at fault for yours not doing so well. My own are doing well in slightly acidic, sandy loam in full to partial shade. For some reason this seems to be a down year for their blossoms altho' a few varieties are apparently thriving. Keep in mind that thanks to weather conditions, many times perennials have good years and bad years. A gardener learns to accept both rather than expecting a garden to perform exactly the same year after year. This year my Hellebores/Lenten roses produced nearly 50 blooms whereas I was lucky to see less than a tenth that many last year. Don't rule out/ignore adding/incorporating other shade-tolerant perennials in your shady garden beds--Tricyrtis hirta/toad lily, Polemonium/Jacob's ladder, Alchemilla mollis/Lady's Mantle, Aquilegia/columbine, Mertensia virginiana/Virginia bluebells, Hosta, Dicentra/bleeding heart, Brunnera/Siberian bugloss, Heuchera/coral bells, Pulmonaria/Lungwort, Chelone/turtlehead & Cimicifuga racemosa/black snakeroot, Atherium japonnicum/ Japanese painted fern & Japanese sedge grass. They'll provide both foliage & color contrasts. The majority of the plants mentioned above can easily be grown from seed via winter sowing or else by division + you can trade for seeds on the Seed Exchange forum. It's been my experience in recent years that gardening doesn't need to be terribly expensive I you're willing to work hard.

A lot of the literature used to report S. canadensis in the south (some still does). It was later generally agreed that those were misidentifications of S. altissima. S. canadensis has mid-stem leaves that are serrate, with the largest teeth greater than 1.5 mm long, and involucres 1.7 to 2.5 mm high. S. altissima has leaves that are entire to serrulate, and involucres 3 to 4.5 mm high. They look very much alike in photos. You can see from this BONAP distribution map that S. canadensis is now reported to be no further south than the southern Missouri border.

@cactusmcharris, interior BC Z4/5 Did you see where I circled, where I plan to cut? On the small side shoot flowers it's easy to see that they are flower shoots. on the large/central flower the stem appears to come directly or be a continuation of the base of the plant, so I don't want to cut off too much of the the main plant.