I'm not always a fan of "plant awards" but this group of plants have impressed me. Haven't tried them all but Walker's Low cat mint, David phlox, Sunny Border Blue veronica, Rozanne geranium, Goldsturm rudbeckia are some of my favorites. The only one I've had trouble with is Butterfly Blue scabiosa but may be due to my pH.

Here is a link that might be useful: Perennials of the year winners

I like the Jolly Bee geranium much better than Rozanne. It's shorter (doesn't flop like Rozanne can), has more blooms off and on all summer, and politely spreads.

The purple colored heucheras would be nice in front of all those yellows. I have several different kinds, and love them all, but 3 that hold their color well and get at least 6 hrs of sun are Plum Pudding, Can Can and Hollywood. Hollywood gets a little green in the leaves during the summer, but it's really pretty. It's flowers are coral and it's a repeat bloomer. It's blooming now for me.
I also have g. Jolly Bee. I love it. Mine gets at least 3 ft wide, but you can trim it back some if you like. It usually starts to flower by mid June, but with the crappy weather we've been having, it looks like it'll be a little later this year. Blooms until a hard frost too.
The ones I've mentioned get a hight of around 12" to 14" and get 5 to 7 hrs of sun.

Kat

Pondy,

I grow 'Pardon Me' Daylilies, and yes, they are a reliable filler, blooming most of the summer. They are a little taller than the Stella d'oros, and they bloom more profusely for me than Stella does.

You might consider planting some drumstick allium bulbs mid-garden. They give a nice reddish-purple accent.

Another red idea is Asiatic Lilies, which come in a variety of colors, and I'm sure you could google to find just the one you like.

I like Feverview for white, but I hesitate to recommend it, because it's not well behaved, and spreads all over. Asiatic Lilies also come in white, but when the Asiatic are finished, you're left with nothing but green stems...hmmmm. I bet you'd like something to take over when the Asiatics are done.

Another blue Veronica, (besides the Sunny Border Blue that was mentioned above) that works well for me is Spike Speedwell (Veronica spicata.) If you keep it deadheaded, it lasts all summer.

For Fall, you could plant a few white or purple Chrysanthemums, if you think they will be hardy in your garden. I love mums, but they have become so much work for me in my cold, windy site and I have to mulch them every winter in order to save them from certain death.

Let us know what you choose for your front garden:)

Julie

Thanks for some good ideas, you all.
I will definately try 'Pardon Me' dl and either Rozanne or Jolly Bee geranium.

The bed is smallish, only about 20 long, by about 8 deep.
There is a River Birch on one end, and a blue mini spruce on the other. (Oh, how I wish I had a camera!)

As mentioned, I already have echinecea (pink), lots of blue and purple in the bed, and in the lot line bed nearby.
So working with blue and reddish tones seems in order.

Maybe I will pop in annuals for late summer color.

Now if only I could figure out what to do with the beds along the front porch! Oh well, that will be my next lament. First, how to get rid of the Russian Sage and vinca, then what to plant instead. Pondy