I am still thinking so this is not my answer. What annuals have you been buying? A fellow like you could grow them cheaper yourself. I buy plants I could grow myself too but I am more impulsive than you.

Annuals bloom their heads off in the heat of summer and many have long bloom times. Most of my perennials bloom and then are done. Some will rebloom if deadheaded. You have shade. I can't at the moment think of a yellow and white theme for most of the summer. I think foliage plants would provide the most attractive display for the longest time.

Heucheras are foliage plants not yellow and white and they look better in spring. They are nice attractive plants. July and August are not the best months for them. Sun coleus are annuals in our climate, but I don't buy them every year. You can overwinter them on your basement window sill in plastic tubs and take cuttings in spring. Most bugs don't bother them. Besides needing water they are easy plants. There are some nice yellowish sun coleus but it is not short enough for you. Do you have any luck with hostas? My best ones are in pots and mid summer is not their best time either.

I hope someone thinks of something to help. We like to hear from you.

What time of day does it get sun?
For White flowers - I used to have a big patch of lamium 'White Nancy' and loved it. I don't think you could grow it from seed but it spreads out quite a bit and if I remember right, it was fairly easy to propagate by covering a bit of a stem with soil until it roots.The foliage is silvery so it's still pretty when it's not blooming. Mine was doing great then didn't come back after winter one year. It might be something that would appreciate the good drainage of a raised bed like you have rather than being in a low spot like mine was.
I'm having trouble thinking of something yellow that would do well in mostly shade.

Hellebore is a nice plant but it blooms in winter and has shiny leaves in summer. Little boxwoods in between your annuals would take up some of the space. I have always wanted to grow corydalis but never have. I don't know if it would work or not. It was in a garden magazine and was growing in the East so I don't know if it would even grow here. You wouldn't be impressed by hellebore unless you grow it yourself. You kind of have to grow it to appreciate it.

This post was edited by helenh on Mon, Jul 8, 13 at 21:23

thanks for the feedback
william

I bought a gardening magazine today that had an article about pushing the shade envelope. You could try some sun loving plants and see how they do. There are perennial coreopsis short yellow ones not the one that gets two feet tall. I don't know of any one perennial that will bloom all summer like impatients or petunias. My little yellow annual celosia reseeds and takes care of itself and so do Glenda's petunias but they like sun and are not yellow and white. The old fashioned trailing petunias which reseed unless you have a drought are fragrant when you have a big patch of them. You may be too neat and orderly for them. I have them in my vegetable garden near my zucchini and I can smell them in the evening when I am killing squash bugs. Lambs' ears also not yellow or white but soft grey would look good with something blue or pink. You might also try a cottage garden look with assorted plants blooming at different times - bulbs and lilies, woodland phlox. This purple groundcover comes back for me and is not supposed to be hardy.

Here is a link that might be useful: tradescantia

This post was edited by helenh on Sun, Jul 14, 13 at 0:14

William, I'd put hosta in -- the yellow varieties like Gold Standard and I even have a few Guacamole and August Moon. And I think Christie's suggestion of lamium. I
would have some candytuft for early spring bloom, then lirope, and maybe astilibe, azalea, and asparagus fern. I know these plants will take some sun, because I have them in my Green Room.

Let us know how it all comes out -- and maybe a photo?
Sunny