Limelights seem to be popular! I would grow one if I had more room! The panicle type (limelight is one) hydrangea seem to get very tall, so that might be suitable for your 30 foot fence.

Oh, Limelights can look gorgeous all right. Paniculatas, in general, are also quite sun tolerant so this can become a discussion of which paniculata you like best. Limelight gets a lime color. Vanilla Strawberry has a nice shade of pink. Most paniculatas will start white and then turn a shade of pink; some also have compact versions.. They all will turn deciduous during winter so make sure this will be ok. If you need evergreens then something else will have to do. Paniculatas are winter hardy to Zone 3 and can handle more sun than most others. Check the bloom forms too; some paniculatas, like Pee Gee, can have blooms that flop sometimes. Some people do not like that and others are fine with that. Others are Quickfire, Pink Diamond, Pinky Winky, Unique...

Limelight hedge, 2 pics:

https://www.sorensen-associates.com/wp-content/uploads/2015/12/limelight-hydrangea-hedge.jpg

http://media-cache-ak0.pinimg.com/736x/ef/3b/5f/ef3b5fb3f9adf0ace16aa9087e5b592b.jpg

Vanilla Strawberry, 2 pics:

http://www.raveplants.com/plant-selections/flowering-shrubs/images/Hydrangea-Vanilla-Strawberry-in-landscape.jpg

https://e54055a024bc6fb58d47-f7df714a3b816a175961a96ef2278d84.ssl.cf2.rackcdn.com/11602-Vanilla-Strawberry-Hydrangea.jpg

Pee Gee hedge:

http://search.millcreeknursery.ca/Content/Images/Photos/F272-05.jpg

Smooth hydrangea (H. arborescens) and its Annabelle-like hydrangeas can also look very good too. Winter hardy to Z3-4. These sometimes sucker so you may need to pull the new plants in Spring. Some people report little suckering and others more. Not sure why but, if this a problem, ask the seller before buying. Annabelle itself has weak stems and its blooms flop when they get wet but recent introductions, with white or pink blooms, are advertised to have stronger stems and bigger blooms. Examples:

Invincibelle Hedge:

http://media-cache-ak0.pinimg.com/736x/15/81/4f/15814f4c0f3f545392b9376c0c4b3fcd.jpg

Incrediball Hedge:

https://farm6.staticflickr.com/5488/9214093065_c2036bdc40_z.jpg

Invincibelle Spirit (pink blooms) Hedge:

http://www.greatgardenplantsblog.com/wp-content/uploads/2011/07/Hydrangea-Invincibelle-Spirit-from-Great-Garden-Plants-3.jpg

Incrediball Blush (pink blooms) Hedge:

https://www.provenwinners.com/sites/provenwinners.com/files/imagecache/low-resolution/ifa_upload/incrediball_blush_pink_annabelle_hydrangea.jpg

The shade of pink/white color in pictures may be off sometimes so, to make sure you like the blooms, see the plants in person... if you can.

I have been researching hydrangeas for a hedge too! I have decided on peewee oakleaf hydrangeas for me because they tolerate full sun and require less water than other types (at least based on what I have read). The full size version is quite tall (maybe 8 ft) if your are looking for more privacy. The flowers are white and the leaves turn red in the fall. The down side is that flowers bloom on old wood so you may have to winter protect it but you are in a warmer zone so that might not be necessary. Good luck!!

Where you are matters to what will grow well, so it would be appreciated if Coalred88 gives an indication of state or nearest large city. Specific site conditions such as soil moisture and light levels are important also.

Panicled hydrangea (H. paniculata) is tolerant of all day sun in my area with no supplemental water. Oak leaf hydrangea (H. quercifolia) is borderline hardy for me, so I don't use it since most winters I would lose flower buds and some winters would have significant die back.

Smooth hydrangea (H. arborescens), big leaf hydrangea (H. macrophylla), and mountain hydrangea (H. serrata) all are happiest with shade during the hotter part of the day, and so do best in morning only sun. The last two are not as hardy or as resistant to late spring frosts as smooth hydrangea and so need protection to bloom well in some areas, tough to do with an entire hedge.

Smooth hydrangea and panicled hydrangea set flower buds on the new growth each year so you don't have to worry about flower buds wintering over.

Coalred88, what height and width of plant is of interest? There is quite a size range depending on species and cultivar. Also, how much sun and at what time of day is there sun in this spot? Can you add a photo to help us visualize the area?

I am not to far from St. Louis. The area is well draining and being located on the east side of a two story house is protected from the evening sun. I was thinking maybe 5 ft tall max and something that's not going to fall over. I like the Mophead type but also liked the pic of the vanilla strawberry Luis posted above. I am going to be replacing the fence with something similar. The posts are rotten and on the other side is my retaining wall and about a 8ft drop. I appreciate everyone's input so far.

That is going to look fabulous with hydrangea blooms! The other type I was looking into that hasn't been mentioned specifically is quickfire, which is a panticulata. It is known to bloom earlier than peegee and limelight and to have great fall colour. I also wanted to mention that mopheads wilt really badly under the hot afternoon sun (personal experience). It doesn't kill them but it's not pretty.

I think hydrangea paniculata, Quickfire, would look beautiful there. I agree with Jen Loo. The Fall color change from white to pink would be beautiful.

H. paniculata Quickfire in my garden is more like 6', but is my favorite hydrangea, blooming for a full 4 months. Some other H. paniculata cultivars that should fit your needs: Little Lime and Little Quickfire should stay within your size range. Bobo will max out at around 4'. White Diamond will stay around 5'. In making your choice, look at how large and dense flower clusters are, and whether they weigh down the branches to cause bending down.

Thanks for the ideas. It looks like some type of paniculata will best fit what I'm looking for. Now I just need to get lucky and find some on sale so I don't have to spend an arm and a lag to do this lol

My recommendation for reasonable prices are etsy and home depot! HD ships many plants now. On etsy you can get smaller plants for low prices. Depending on if you can wait until they grow large!

I'd rather have something evergreen there and put the hydrangeas elsewhere, where there was a solid backdrop for them.

It looks like you live in the country so just a reminder that hydrangeas can be attractive to deer. In my yard, they especially love the oakleafs.

Last year, the Home Depots in my area got a ton of Quickfire and Limelights in. Every year in mid-July they mark their shrubs at 50% off, so I picked up a few good sized Limelights for under $20 each. I know that HD's stock varies locally, but just something to keep in mind if you can wait until summer to buy. If you do this, I would keep them potted and baby them until the weather cools down in September and then plant then.

The new fence is going to be taller so I should have a relatively solid back drop. I think waiting til later in the year to put the plants in is a good idea also. I will be able to get better pricing and it will be easier on the plants, especially if we have a scolding hot June like we did last year. There is a nursery close by that just recently opened to the public. It was solely a wholesale distributor for years. I bet they have all kinds of varieties to choose from.

Perhaps it's a trick of the photo, but right now the bed looks really shallow. You want to accommodate the full width of the shrub. IME it isn't easy to control their size via pruning since they regrow quickly.

Ya I have not done anything to get the bed ready yet. I'm going to give it plenty of room. . . Once I make up my mind on what to put there lol.

Coalred88, have you decided yet? Can we get an update photo?

I ended up going with limelights I couldn't resist ha. I asked a friend of a friend who does landscaping for a living and he told me I would love them there and if I needed to I could contain there size. I'm not as concerned about keeping them to a certain size as I was earlier this year. I picked these 2 up on sale last week. They were the last 2 left. Planted them 5 feet apart and the bed is roughly 6 feet deep. That's a little quick fire next to them on the far right. It's been in for over a year and really doing well. Couple more LLs and il be set.

Those limelights look great and already a nice full shape!