The color of my rain soaked oakleaf leaves is similar to your shade of
greens and my shrubs have received much more rain than yours so I highly
doubt you have a moisture problem. While sun deprived for the last two months, my oakleaf hydrangeas have not reduced the production of chlorophyll, which makes the leaves change color in the Fall.

Besides, I would not expect a water issue if you have sandy soil. Now, you could test that: insert a finger into a soil daily, always at the same time of day, to see how the soil feels. If it feels wet and there is no explanation (like it just rained), there may be a drainage problem. But with sandy soil, it is probably not drainage but a case of not having some nutrients. The color change reminds me of the color that some leaves turn to when wholesaler strive for nice purples on mophead hydrangeas.

So I would monitor the soil moisture daily (use the finger method or a soil moisture meter to add 1.5 gallons of water per watering when the soil is almost dry) and I would see if I can find a soil kit that analyzes soil samples to see if minerals like nitrogen, phosphorus and potassium are at high or low levels. Then based on the results, I would take appropriate action.

Luis

PS - Have you ever done a 'formal' soil test?

No, I have not done a soil test, but I haven't amended my soil at all either. I thought if hostas grew well there then so would oak leaf hydrangeas, since the ph level doesn't really affect oakleaf hydrangeas like it does with other species hydrangeas. I also contacted the Kansas State Research and Extension, and they said that based on what I described and the photos I submitted, they thought it was transplant shock. The hydrangeas aren't getting all the nutrients they received when they were in their nice comfortable pots. They think if I make sure they get adequate water without making the soil boggy and give them good care, without loving them to death, then they will bounce back after a couple of weeks. We've gotten plenty of rain with more on the way, so I think I will patiently wait and see what happens.

Hostas will grow almost anywhere (soil type), except extremely deep shade. As they're tuberous, they store moisture an nutrients down below ground. The tubers can burrow right through dryish heavy clay, or can grow in nearly standing water. Because of this, I don't recommend they be used as a benchmark to grow other plants and shrubs, except maybe daylilies (not Asiatics).

I think your photos of your new oakleaf looks fairly healthy. The leaves are perky and a little color change doesn't mean that much for a new plant. It is just going through some transplant shock. If they turned black or wilted (with adequate moisture in the soil) then I'd be concerned.

Eh, just going by what I've experienced personally. The hostas "in" water must've been just above the water table. I've read many places that hostas have tubers but I guess it's a common misconception.

My oakleaf
hydrangeas are still looking healthy and no more leaves are turning
red. I am beginning to see a tiny bit of
new growth on them, which tells me that they are recovering from the transplant
shock that I am now sure was the reason why they were changing color in the
first place. Thanks to all of you for
your wonderful advice. Although I didn't
do anything different to the plants because of the advice, the advice you gave helped
me not to hit the "panic button" and do something rash that really
would have caused more damage to the plants. Thanks again.

Yay, I like to hear that. Give it a few years and you will be amazed at how big they can become.

I visited a man in the hosta society of GA a week or two ago and he also had many hydrangeas - some named and some grown from seed. I think he said this is Harmony which has an odd bloom shape unlike most oakleaf hydrangeas.

He also grows many hostas from seed and culls the ones he doesn't think will make the cut. I ended up with a couple freebies and my friend took six. I was wondering if we could get them all in my truck since she also got a big climbing rose with long canes (the longest was probably 8 feet).

He was keeping most of his blues and yellows though (sigh)

He was getting rid of a lot of streaked ones since he said they just aren't stable.

I was probably wrong on the hydrangea after looking at it closer. I think that was a volunteer. Here is Harmony.

Nice photos. I love the foliage. Snow Queen's flowers are held upright though instead of hanging down like many oakleaf hydrangeas do.

The Dallas Arboretum had a Harmony that produced blooms like in your picture above. But they did some work in some areas "without consulting with me" -hee hee hee- and last time I went back I could not find that Harmony. If they got rid of it, I wish they would have asked for takers!!!