need help with choices for perennials

Hi! After 13 years of living in my house, I finally got my planter boxes to look decent. However, I want them to look spectacular!!!

The bottom part is ok, I'll just forget about the coleus (victims of a late frost) and fill it with the same pretty flowers as before. Maybe I'll choose one colour for the outskirts to act as a border.

For the top, the green sweet potato vines were pretty but were eaten alive by ants! I think I prefer the trailing bacopas instead and will replace the SPV with them. The clematis and Japanese blood grass were a bust because they got no sun at all -- I didn't realize that the roof overhand would block all the sun! The bush (forgot name) is ok, I don't want it to get much bigger than that. I chose it and the hostas for their variegrated leaves because I didn't want plain green (unless it was bright green like the SPV).

So, I need to pick out some more plants for the top part. It's got quite a bit of dead space between the existing plants. Any suggestions? I live in Toronto so what's a perennial to you might not survive my winters.

Here's another pic of the top part

How much sunlight & orientation? I'm also zone 6a.

bottom gets part to full sun. Top front is part sun. Back part of top (where clematis and grass is) is full shade due to roof overhang

How about some Astilbes .... nice foliage and a wide variety in the color of the plumes.
they are cold tolerant -- i have some in my zone 4 and a few in my zone5.

I had to look them up first because I didn't know the plant but now that I've seen some varieties, they are very pretty! Definitely on my "maybe" list.

Thanks!

Like your planter boxes. Are perennials the way to go? I perennial garden north of you and there are very many perennials that can be used in perennial beds. In your situation, however, there are several problems with perennials. If you want them for the flowers, most only bloom several weeks in the year. That means you are better to go with perennials which have attractive leaves over a long period of time. See you already have a variegated hosta. Astilbe have been suggested. Very pretty foliage, but I find they need a fair bit of water, especially in a sunnier location. Do the planter boxes tend to dry out?
There are some relatively short lived perennials (several years; depends on the soil, etc.) that do bloom for a long time through the summer. Coreopsis
(yellow flower) and gaillardia (yellow- orange-reddish) are pretty hardy, smallish plants, sun-loving and drought tolerant. They do gently seed, at least in my perennial beds. Don't use expensive fancy less hardy varieties (likely to die). Try 'Sunray', 'Sunburst', 'Early Sunrise', 'Sterntaler' or the like for coreopsis and something like 'Kobold' (Goblin) for gaillardia (blanket flower). There could also be a problem with excess (late winter?) thawing and freezing (not good for perennials) with planter boxes.
Another perennial which is small, it flowers for an extremely long time, has pretty delicate foliage, is quite shade tolerant, does best with adequate water, gently seeds and is easy to pull up and get rid of, is Corydalis lutea (golden corydalis). Great little plant. Warning: some of the other corydalis are either terrible seeder, or expensive and not hardy, or flower for a short period of time, or die back to corms which you can't find to get rid of.
Might try Rudbeckia 'Goldsturm' (orange coneflower), blooms six weeks, very hardy, sun, not that tall, excellent plant.
Sunny

Wow, lots of info! I am looking for mostly foliage perennials for the top bed as the bottom will have plenty of blooms as it is.

Foliage plants... look at Heucheras too. they come in various colors. Great yellows and purples. Lime Ricky would be great combo with the various purples they have too. I have peppermint spice, and it almost has a red veining in green leaves. very pretty. But -- they have come out with some really neat colors.

thanks! I'm going to be printing these out before heading to the garden centre at the end of April.

http://www.terranovanurseries.com/wholesale/modules.php?name=Content&pa=showpage&pid=346

here's a bit of eye candy....