Diggin, it's hydrangea macrophylla. The exact name of your particular variety can be hard to come up with on a florists plant. If you planted it last year and it wintered over with its flower buds intact without protection, you may have received a hardy shrub, often they are tender to about Z7 or so - they don't always perform well in gardens - garden placement wasn't the original growers intention :).

With just a handful of exceptions, they bloom on growth produced the previous year, or 'old' wood, so winter or Spring pruning (other than deadheading old spent flowers) should be avoided. If you are trying to keep the size somewhat compact, you could prune approx 1/3 of the stems that have had flowers on them down low at the end of each season. The result is a plant that is completely renewed every three years that hasn't gotten as large as its potential. Size depends somewhat on climate(winter injury/dieback)and variety but 4x4' or larger at maturity might be average.

How much water how often will depend somewhat on your soil type. If you check at the base of the plant and it feels dry below the top couple of inches, water - even if that means daily in extreme heat. Mulch will help to cool the roots and conserve moisture. That much sun is more than is recommended, most hydrangea macrophylla appreciate some mid day shade when the sun is at its strongest. I don't see the foliage looking especially burned in your photo though, however your flowers are suffering from too much sun and those are browning out prematurely.

If your soil PH is high, treating it to keep flowers blue will be on ongoing process - even more difficult if your water is also alkaline. I let mine bloom at whatever color they will arrive at naturally (it happens to be blue in my acidic soil) and don't try to control the shade, so I'll let someone else add some input there for you if the color is important to you.

I didn't specially answer your question about repeat blooming - there are just a very few, very new varieties that will bloom on both old wood (wood produced the previous year) and new wood (the current years growth) too. The chances of your florist plant being one of those few is unlikely so - no, deadheading will not encourage repeat bloom same season. Sited where they have some mid day shade, or in a season less extreme than this one has been in many parts of the country, the period of bloom is usually long enough to satisfy :)

Hi Morz8 Thanks so much for responding with all the info! It appears MOST of my blooms are on new wood?? theres one brown stem that has blooms but the rest are all green . I planted it last fall. Does this help narrow it down any? Is it still considered a mophead?heres close up pics of the stems. With regards to watering is about gallon a week ok? Thanks again!

OK went back out for another look.I found 2 more old wood. but there does appear to be new wood or is the old wood buried too low? I've been watering the past 2 weeks whenever I see its wilting cause of the high temps heres a pic of the blooms now.