Hi Kelly, welcome to the Cottage forum.

I guess the question would be what effect do you want?

Roses and hydrangeas go dormant in the winter. You would have no foliage.
Some roses bloom once and some types are repeat bloomers. Both rose bushes and hydrangeas are relatively the same size.

I don't know your zone but hydrangeas can burn in full scorching sun. They like morning sun and afternoon shade.

I've attached a link below of an old post. It shows pictures of a lush beautiful border created with a variety of plants.

Here is a link that might be useful: My Red Bed - Second Year

The red bed, still stunning every time I see it.

I don't think these two plants will work together. I know for my zone, hydrangeas need almost full shade while roses want full sun, generally.

If you want a privacy hedge, consider some evergreens mixed in with the roses if it's sunny, or with the hydrangeas if it's shady.

Speaking as another Ozark gardener, the only hydrangea that does well for me is Annabelle and she is planted on the east side of a building and very near the hydrant and is under full mulch. Hydrangea paniculata could work also.

I am doing a new shrub border between the house and the road awaiting the death of the trees near the road. I am using a mix of things, lilac, forsythia, viburnums, oakleaf hydrangea (in the shade of an evergreen), a couple of hydrangea paniculata, a birch tree and an Amur maple tree. I want one or two evergreens, but don't want to screen my view completely...if so, I would use lots of evergreens. Then between these shrubs, I hope to keep a layer of leaf mulch and clumps of very easy, carefree perennials and a rose or two.

What the others said: hydrangeas and roses don't mix really well, since they have very different growing requirements. Plus you would get nothing but a bunch of sticks in Winter, which may be a problem if you don't have a snow cover to make up for it.

If your area is sunny you may consider the roses with lavenders, catmints, sedums, even some tall hollyhocks in the background, salvias, santolinas and the like. If you want to mix shrubs, red and yellow twig dogwoods will give you Winter interest. Also some evergreen shrubs that can take sun, as Token said. Brenda's red border shown above is a stunning source of inspiration for such a bed.

If, on the other hand, the area is shady, you can grow the hydrangeas and mix in shade loving plants. I'm not familiar with the growing conditions of the Ozarks, but I suppose things like hollies, sarcoccoca, aucuba and some viburnums would do well mixed in with the hydrangeas. Foxgloves would look stunning growing there as well and would provide you with an early burst of color before the hydrangeas kick in.

Eduarda

Thank you so much for your input...this is why I pose these questions here. You all have so much experience that I can learn from.

Kelli

There are hydrangeas for sun as well, I suggest Bobo hydrangea as a companion for your knockouts, the fresh limey white blooms will complement the roses and they can easily be maintained at a similar size. Enjoy!