A couple of suggestions...

For the partly shaded area, check out Prunus caroliniana 'Bright 'n' Tight', a dwarf Carolina Cherry Laurel. This selection of a native broadleaf evergreen gets about 15 feet tall but has a rather narrow, columnar habit that makes it a good choice for screening. It likes part sun/part shade, and moist soil is fine.

In sun you might look into a selection of our native red cedar (which is actually a juniper, Juniperus virginiana). A relatively fast growing variety is one called 'Burkii' (pronounced "burk-ee-i"), which has really pretty blue-green feathery foliage. This one gets kind of wide at the base over time, so if you're dealing with a narrow space you might want to look at a different variety. I've seen Burkiis grow to 20 feet tall in less than 8 years. They're very dense, too, you can't see through them at all if they're grown in full sun. This plant will get 30 feet tall or more with time.

Thanks, Soeur. I like the juniper - I will look around and see if I can find one for another spot. For the full sun area, I picked up some Green Giant Arborvitaes which, if they take, will make a great screen, as well as a wind-break, which is also desperately need on that side of the property. :) We're working with a half-acre backyard that's completely bare. So much to plant... :) Does bamboo grow well here in TN?

Some think bamboo grows almost too well here. Golden bamboo has escaped in many locations. It's not taking over on the scale of japanese honeysuckle or kudzu, though. Bamboo does make a great screen, and its vertical nature works in small spaces. It tends to send out underground runners which can produce shoots a surprising distance away from the parent. If you're willing to chop those vagrants out to contain it, bamboo is a good choice.

I think you'll be really happy with the Green Giants :) I have a couple along the outside of our fence, in a grouping of fast-growing evergreens. They have doubled in size in a year. Yikes! I am starting to be a little afraid of the trees I planted. LOL

I also used a Leyland Cypress (I know, but hey, it's fast), but my favorite is the Japanese Cryptomeria (Yoshino). Oh my gosh. What a GORGEOUS tree! It has not put on at quite the rate of the Leylands or the Green Giant, but it did grow at least a foot or maybe more in a year.

I had bamboo at the other house, and the great thing about it is FAST, and you can use it in a very narrow space where you'd never be able to use a tree with any kind of footprint at all. We had neighbors whose deck overlooked our backyard (much like a viewing platform at a zoo...). There was only about ten or fifteen feet between our houses. The solution was to put in a stand of bamboo, contained in about four feet of space. We had a great screen between us by the second year.

BUT, a word of caution: We went to the trouble (and expense) of having someone come out and help us dig out the area and put down a barrier so the bamboo wouldn't escape. This barrier, if I remember, was about 18" deep. Well, guess what? It is reported to have jumped the barrier and is running into the yard. Yipes.

But I still think bamboo is just about unbeatable for fast screening. Hopefully the barrier will at least slow it down. ;) If you have the space and are willing to manage new shoots, I say go for it. I love how it looks.

"This barrier, if I remember, was about 18" deep."
18" is pretty shallow for bamboo unless you have a really small variety. Most of the bamboo barriers I see are 36".

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"...ultimate height doesn't matter in either location - the taller the better"
Green Giant's "mature height" (when they start to slow down some) is 40' to 50'.
Leyland's "mature height" is 75' (can eventually grow to 115'+).
When you say ultimate height doesn't matter, I just want to make sure you mean that. The height's you gave (8' & 12') are pretty short and there are many many many possibilities that would easily quickly take care of that height.

A couple of other things you might want to consider:
Planting a variety of trees or shrubs can be better than going with only a single type. Not only are multiple types more interesting, but they are also less likely to be bothered by pest and disease (monocultures are bad about that). And, if one tree dies in a collection of different trees, it usually doesn't look as weird as if a single tree out of a row of clones dies. The "missing tooth look" can be severe in straight rows and in single-type plantings.

Brandon, you made some good points. Any tips on how to use multiple species along a fence and make it look right? Should you use 3 different things? Should they all be similar in height? What about shape and form?

TIA,
Janine

A variety of vegetation is nice for a natural border. Maybe look around your neighborhood & see what is being successfully grown. Happy plants make for happy gardeners.
Experiment & see what grows best for your space.

Janine,

Plans have to be made on a case-by-case basis. If there's room to plant random groups of plants in at least slightly varying distances from the fence, it will look more natural and minimize visual issues if one tree or shrub is lost. Varying sizes and shapes will also increase the natural look. Sun exposure should be considered; a small sun-loving shrub shouldn't be planted behind a tall tree. This kind of thing has to be considered for the particular location, and I don't know how to give more general advise that will work in each different case.

The bottom line is to consider this type of thing when you are making plans. There are some situations where the random/natural look may not work. If you have a very narrow location, that will limit your choices. Just being aware of the possibilities should help when making plans.