More modern varieties of butterfly bush come in more dwarf forms. Rhododendrons usually can get huge, as can the Viburnum . My Oakleaf Hydrangea enjoys bright shade and not much direct extended Sun.

Some of the red twig and yellow twig dogwoods would also give you stunning winter interest, especially planted in a row.

Have you considered shrub roses? Rose of Sharon (Hibiscus syriacus)? Will they grow in your area?Pyracantha. Chaenomeles. Other Viburnums. Hamamelis. Corylopsis. Golden Currant?

Pinus mugo is quite low - do you want all the other plants to be the same height?

I think ninebark Diablo gets condsiderably bigger than most butterfly bushes. Ninebark 'Summer Wine' is smaller growing and more compatible size wise with butterfly bushes.

Bogturtle, good to know about Hydrangea and sun. I have one spot that may work. I'll have to watch over the summer to see how sunny it is. Nothing is going to get planted till fall anyway.

Roger, I'll have to look in to the dogwoods a little more. I honestly haven't decided if I like them or not. That may be because I always see them badly sited and mangled or neglected.

Flora, no I hadn't considered shrub roses yet. I will now. I'm looking in to your suggestions since I'm still learning what will grow here. I did pass a Pyracantha hedge yesterday which I wouldn't have noticed except for your suggestion. I have a neighbor with a Rose of Sharon so they will grow here too. I think I have the evening free so I'll look in to your other suggestions a litte more.

Felisa, do you know how the color compares on the two ninebarks? I had a Diablo when I lived in PA and loved the color. I don't think I have seen the Summer Wine in person yet.

Thank you everyone for the suggestions. They have gotten me thinking which is exactly what I wanted. I'm not looking for things that are necessarily uniform in size. In fact "hedge" is probably too formal a word for what I am thinking. "Screen" or "Background" might be a better way of putting it. Growing in Denver is a lot different that growing in PA so any comments, suggestions or questions to make me think are appreciated.

We have what I believe to be hydrangea limelight on the west side of our house. It is 6 ft tall and was probably planted 4 years ago. It has done quite well in our heavy clay soil, plenty of sun and little care on my part.

I have an oak leaf hydrangea on the east side of some trees. I believe the oak leaf does well in part shade situations.

Consider Sambucus (elders). A Black Lace and a Sutherland Gold look great together.

I was just out admiring all the beautiful small white fragrant flowers on my Philadelphus Snowbelle. I planted it last year in the spring and it bloomed and bloomed until Sept/Oct. This year it is full of blooms. Stunning :-)

How bout a rose? Perhaps a rugosa like the muslin rose (blanc double de coubert) or Hansa;

flowering almond;

and depending on your timeline- if you are patient, a tree peony can get very large given the time. There are some to die for tree peonies in my town.