Stylophorum diphyllum has 3-4" bright yellow flowers off & on all summer (heaviest bloom is in spring), Actaea/Cimicifuga racemosa has large bottle-brush white flowers that stand out well in shade, blooming in July or August.

How could I forget Japanese anemones!

Thanks so much. If you think of anything else, please post.

I have coneflower blooming right next to my astilbe and hosta, monarda just a dash over where it takes advantage of a bit more dappled sun than shade, goatsbeard which gets white plumes in late spring/early summer, yellow loosestrife (which doesn't get much bloom in shade, but is nice and bushy with a large variegated presence.

Lobelia Cardinalis gives a PUNCH of colour and is blooming right now until October.

I also have Rose Mallow blooming in the shade and the colours are quite spectacular.

Most daylilies will take a fair bit of shade and still bloom with large colourful blooms.

Firewitch Dianthus and other closely related dianthus will give a big punch but are low to the ground so that may not be what you are looking for.

Echinaceas (wide colour variety now avail) so well in a fair bit of shade, bloom mid to late summmer and early autumn and the goldfinches LOVE it.

My large iris do well in the shade and are a rich punch of colour in spring/early summer.

I also have Asclepias Tuberosa in the shade and it blooms just fine with it's neon orange blooms that the bees and butterflies can't resist. Blooms mid summer to early fall.

Another low growing punch of colour for shade is Pulmonaria of which there are many nice varieties and colours to choose from now. Mine is the old "sacharata" but there is strawberry splash which is similar, a white variety and several others.

My butterfly bushes, do pretty nicely in the shade and have many large blooms. I have the "Royal Red" variety which is actually more "Maroon" than red and I also have the purple "Davidii" and the blue/purple "Nanho blue" which is nice for it's misty green foliage. Nanho blue is smaller and more delicate looking but the "Royal Red" and "Davidii" can grow to be white good sized, well behaved shrubs.

Thanks for all the suggestions. I'll look up the ones I'm not familiar with. Monarda & Echinaceas & butterfly bushes were a bust for me in the shade. Cardinal flower died after one year. Yes, I have some purple Irisi that I could put there for spring color; thanks for reminding me.