Don't cut the plant down... or even at all! Hydrangeas bloom on old wood, so you'll lose blooms come spring if you do. You may cut off the spent flowers with abandon.

I know hydrangeas can be rather unsightly this time of year. I have several myself and in fact just relocated three today to a less conspicous spot (from by the front door to backyard) due to their less than fabulous off-season look. It is tempting to wack them down, but since I know I can't, was tired of being greeted by twigs, so I moved them. I think they'll be happy in the backyard though.

Depends on the variety. Annabelles do not have to be pruned. Yes, dehead the old blooms.

I'm no expert, but not all hydrangeas are the same. The endless summers you can prune at any time. I do that because mine is in an area where it gets big fast and that way I get a second flush of blooms during the summer.

Paniculatas bloom on new wood which means you can prune after they finish blooming. I think the same is true of Annabelle. Which means you could prune now through very early spring ... before new growth appears.

If it were me, I wouldn't prune at all. The plant will have more strength if allowed to grow without pruning, especially when it's this young.

Here is a link that might be useful: info on Annabelle pruning

Annabelle is the best known arborescens hydrangea and blooms on new wood. For now, keep it the way it is so it will grow and get big. But if you were to prune it, it wouldn't hurt a bit.
The "old wood" thing is mainly for macrophyllas (those big blue ones) but even some of those (Endless Summer, for one) will bloom on new wood.

My favorite hydrangeas are the paniculatas.

There are a lot of hydrangea sites with great info, look at Michael Dirr's to start.

To bush out your Annabelle, prune it by 1/3 each year and it should fill out nicely. But not this year, it's too young.

I think we posted at the same time, Natal!

BB, I planted my first Paniculata last month ... Little Lime. Was excited about finding a hydrangea that liked the sun.

Paniculatas are so great, beautiful, hardy, easy.
I'm sure you will want more over time. I have 2 Limelight, 8 Regular Peegee and 3 of a pinkish variety whose name is escaping me at the moment and I still want more.

I just wish I could get an oakleaf to grow. First one I planted years ago did great for a few years and then up and died. I planted a couple dwarf oakleafs last year, but they're not growing at all. Finally decided to give the variety one more chance and planted another this fall. I seem to either have too much shade or not enough when it comes to that variety.

I have an Alice I have moved several times before I found an optimal site: bright light under a crepe myrtle with fairly moist soil. Other quercifolia varieties in deeper shade and drier soil are alive but don't thrive

So sorry I misinformed you about the old/new wood issue, Amj! You've got lots of good advice now. Good luck with growing your Annabelle and hope you enjoy!

Thanks everyone. I'll leave them alone.

I can see where the plants were cut at the nursery prior to us purchasing them. There are a lot of cut branches about 18" long inside the plants that did not grow or bloom over the summer. Is this normal? I was afraid to add to that by cutting them this fall. I would love for them to get bigger and stronger, so they'll fill the space a bit more.

All hydrangeas will produce dead wood but what I do is in the spring, right after the leaves have emerged, is cut out the dead wood.
Hydrangeas can be really tricky, unlike most plants that you can scrape with a fingernail and see if the wood is green underneath, the wood might be alive but dormant on a hydrangea and you won't see any green. So wait for the leaves, and, the leaves will emerge more slowly on some stems so wait until all stems have leaves then remove dead wood.

I love hydrangeas, they are one of my favorites, had 10 varieties at last count (till DH cost me a few, but we won't go there ;). Can't emphasize what bumble said enough, don't cut till you see green leaf buds emerge. I'm in zone 5 and have had some that looked completely fried from winter finally emerge in very late May.

natal, my former NDN had the most beautiful oakleaf. It was big, old and draped over our privacy fence in back. I loved it! They retired and moved, a relative bought the house, and promptly yanked out a lot of very nice, mature plants and trees, including the oakleaf (and one very beautiful Japanese Maple). Couldn't believe it. :/ I still miss those blooms.

You can prune Annabelle down to the ground but since this is it's first year I'd go easy on that and prune a little higher, just in case. as it ages if you don't prune it hard you'll end up with a plant that flops over when it sets flower. The heads are heavy and the stems weak. Even still I find myself supporting the plant with fencing to keep the entire thing from leaning over. That's why you want to prune it as low as possible, so the next years growth won't get too tall before it flowers.
Annabelle (i.e. Paniculatas) also spread unlike the other hydrangeas so be prepared for it to grow out as well as up. I have a much larger plant than I started with which I love but if you've planted yours too close to another plant be aware eventually it will encroach.

flyingflower,

After reading your post, I am thinking that might be my problem with one large I believe Annabelle in my backyard.
It was there when I purchased the house. I have been here 2 years now and I love the plant but it does get large and is always drooping with very large flowers. I have never cut it because I thought that I was not suppose to. I am in zone 4-5. Perhaps that is my problem and I should cut it back. How much should I leave on it from the ground up?
Also is it too late now to cut it.
Thanks for any help.

Not ff here and although I know a lot about hydrangeas, I don't live in your zone so won't comment, but Annabelle is an arborescens and not a paniculata, a little different.

Like a banana and a plantain, both fruit and similar but different.

I stand corrected, thanks for pointing that out Bumble, I got lazy and didn't look it up. One of my other hydrangeas is a Paniculata. I've got so many of different varieties I get their names mixed up.

It's not too late to prune your Annabelle, on the contrary you want to wait till it goes dormant to do that so when the leaves fall off and it's nothing but "sticks" then prune. I like to prune down to the first "eye" just to make sure it will grow back.