Linda,
I had never heard of a hydrangea that flowered all summer! According to the website below, yes, you should deadhead to promote bloom. They also give you more tips on caring for it.
K.

Here is a link that might be useful: endless summer hydrangea

I want to grow some. Do I plant in the fall? And what variety? I live in Rome, Ga.

Linda you can remove the old blooms if you like, it will encourage new growth from which new blooms will come. The endless summer blooms on both old and new wood and Mikeyjoe, fall is the best time to plant in the south.

I have had good luck planting during the summer rainy season. That's the best time to root tip cuttings too.