Like all hydrangeas, the flowers will form at the terminal ends of branches and lateral stems. If you cut back the plant to a uniform height (i.e., "sheared" it back like giving it a butch haircut) and assuming all the new growth developed at the same rate, then yes, the flowers would all be at the top of the plant.

You may more easily develop the look you are seeking if you pruned it into a gently rounded shape - taller stems in the center, shorter around the periphery. And the ability of any of the reblooming hydrangeas (like the Endless Summer® series) to bloom on old growth is enhanced if they do receive proper winter protection. Otherwise you will be relying only on the ability to bloom on new wood, which may or may not provide satisfactory results.

I am exited to know that the flowers will not be at the botton of the hydrangea. The Light O Day is very sensative to our winters even with winter protection. So I am tired of looking at burlap in the spring for no good reason. I love the foilage and ever year from mulching it heavy at the bottom the flowers survive at the bottom. So thats why I ask if I just cut it down every fall to 10-12 inches and mulch it heavy where the flowers would develope on the Hydrangea. Thank you for the response!

I'm not sure I was very clear in that response :-) If you cut it all back to a uniform height and those remaining stems are affected by winter cold, you may not have any viable growth except what comes from the root crown - that is, those stems may be dead or if not, any buds they may shelter potentially destroyed. If that is the case, then yes, the flowers would be lower on the plant, where the viable growth is occurring.

Does that make sense ?

Thank you for your help, but I am still a little confused. If I cut it down in Fall to 12 inches and completely mulch the stems. Say I get luccky and the buds make it through the Winter under the mulch where do you think the flowers will be located on the plant once it grows into the summer. The Light O Day Hydrangea only blooms off of old wood.

You might want to double-check - 'Light O'Day' hydrangea is listed by most sources as blooming on both old and new wood (developed by Bailey Nurseries from some of the same hydrangea stock that resulted in the Endless Summer series).

Here's my take - if it only blooms on old wood, cutting back to 12 inches or so and mulching will eliminate flowering anywhere on the plant. You have cut off the old wood that produces the flowers, just as you would have done with the same procedure on any other mac that is not a 'rebloomer'. Minimal to NO pruning of these is recommended to ensure flowering.

If it blooms on both old and new wood, you've still cut off the old wood and any flowers associated with that but new growth (new 'wood') will be produced from the root crown. This can produce flowers but they will be low on the plant. New growth can also emerge from the older, cut-back stems provided they were not killed by winter cold and these may or may not produce flowers. Depends on the plant, its location and growing conditions and the summer weather.

Regardless, you'll still have the foliage :-) The traditional variegated mac, 'Mariesii Variegata', is not a heavy or reliable bloomer except in areas that are pretty much ideal hydrangea growing locations (PNW, Georgia, etc.) but many still grow this plant just for the foliage.