Hello, LukenLulu. I am obviously not in Colorado so I cannot accurately comment on the effect of your summer sun on the Limelight's leaves. Here in Texas, the leaves are scorched if exposed to sun after 12pm. But your sun is not as strong as it is here in the summer so, you may be able to grow Limelight with that sun exposure during the summer.

The less sun, the better though. As it turns out, the green immature blooms on Limelight remain green longer if you expose them to little sun so "less is more". If it gets "too much" sun, the green blooms will turn white faster.

Limelight does get large, about 6-8' at 10 years so the 6' area (space from the fence to the grass) may not be big enough and may require pruning when it starts exceeding its bounds.

To see how others have planted Limelgith in CO, you could try looking around to see if you can find someone (or a city/state garden) and then observe how much sun it gets where they have planted their specimens. And see how big their Limelight has gotten. You could also test the waters with just one shrub and see if the leaves have no problems getting sun from 10am-3:30pm. If they suffer from sun scorch, you will know that is not a good area and you can then transplant the shrub elsewhere.

Hopefully, growers in Colorado will chime in. If not, contact dalepar, who was trying to grow a Limelight as a tree some time ago. If dalepar is still active, you can send him a Garden Web mail.

Luis

I grow a couple Limelight here in all day full sun. They do great here. Even with this past years summer and record over 90 days for the year, I had very few scorched leaves, which I had on almost everything anyway. Just wasn't a good gardening year for people. My blooms didn't last as long this past summer on anything either, but that was to be expected. I can't speak for your area, but here they are wonderful in full sun.
Cher