It, like a number of other pink-flowering cultivars, is pretty stable in its flower color and not overly influenced by soil pH. If you live west of the Cascades, we do tend to have acidic soils so to be on the safe side, I'd topdress with a bit of lime.

They look very nice and seem to be ready for a very productive year of beautiful blooms. I took your advice and bought one each of Blue Heaven and Together, will plant them this weekend. Plus 5 ES I planted in early May so lot of watering to do. But I look forward to a yard with them bloom as good as yours. Hopefully they will all survive and do well. The reason that I am a little concerned is that I planted two hardy hydrageas last summer, they did ok then, but this year so far lot of new branches and nice leaves, but no buds yet. Not sure if I pruned them too early (I was new at this last fall so I may have pruned them last fall when they are done with blooming). but now I know better. Thanks for your help again. I learned so much from you and other experienced posters here.

Some companies -on their own- change plant names to try and improve sales so it may be that they are the same plant. Peole want to see a real red hydrangea bloom so they advertise that in the name. But so far, the reddest is just a dark shade of pink. RS is probably just 'eh, ok' shrub from what you are finding out. Suggestion: do a forum search for Red Sensation to see what others have to say about RS. And of course, keep in mind you will often just find complaints, since those who have good stories do not necessarily post good stories. Being macrophyllas, they can handle morning sun but prefer afternoon shade as macrophyllas are understory plants. In the northern half of the US, they can get more sun exposure but, they will certainly do their best if you give them shade in the afternoon or dappled sun. As reference points, down here in Texas, I give my macrophyllas shade starting at 11am to 12pm. Up in the northeast, my mother-in-law had a Nikko Blue in full sun from after 11am thru sundown. These times are in the summer months by the way. In the spring, the sun is not too harsh so you could give them lots of sun in just about anywhere. The sun exposure problem makes the leaves in the summer sunscorch and the blooms brown out from excessive sun exposure. So leaves in direct contact with the sun will turn all yellow -incuding the leaf veins- or all whiteish and then fall down. The leaves not in contact with the sun will remain a normal dark green as usual. Just about all H. macrophyllas can be placed in pots. The main problem -if you want to call it a problem- is that some macrophyllas get quite large and would not look good in a pot not in sync with their eventual size. Say think of a shrub that has achieved a size of 6' by 6' but was in a 4' wide pot. So you decide a bigger pot instead of pruning and then the pot occupies a lot of real estate. And this type of plant -when large- has to be pruned regularly to keep it in check and looking good. And some people do not want an added annual chore. Another chore is bringing the pot inside in cold winters. Large pots are way heavy and problematic to move by yourself sometimes. So there is nothing wrong with growing in pots, just stuff that has to be done which can be a pain.

Hydrangea blooms do not come in true red so take descriptions that mention 'red' with a grain of salt. Typically such shrubs just turn a shade of dark or magenta pink instead. This 'Red' may resist turning blue like other similar ones in acidic soil ... and could even turn purple at very low, soil pH acidic levels... you just have to try and see what happens when the roots "leave" the potting soil after you plant it into your garden soil. Whatever bloom color happens will depend on your soil pH, amount of aluminum & other minerals in the soil, genetics, weather, amount of sun, etc. The patent does not say what color it will get in acidic soil: https://patents.google.com/patent/USPP18450P2/en?q=Hydrangea&q=macrophylla+%27Maltisse%27&oq=Hydrangea+macrophylla+%27Maltisse%27 Thus I would assume that it will resist turning blue and do a shade of pink or maybe even purple.