Im pretty new to gardening but the wife and i did some landscaping this spring and three of the plants were the Endless Summer (2 Originals 1 Twist n Shout) hydrangeas. So far they are doing fairly well but i do have some questions about them.

1. About 10 days ago we had a two day cold snap here in central Iowa where lows were in the mid 30's. Since that cold snap i noticed on some of the blooms that the edges of the flowers turned brown. I also noticed on a couple of the hydrangeas that the leaves started to turn burgandy. It was mostly on the edges of the leaves and not the entire leaf itself. Am i correct that they had a little frost bite and should come out of it ok?

2. We have clay soil here in central Iowa and i planted the hydrangeas near the house where it isnt compacted nearly as much. I dug a hole per the directions and used 1/3 Potting Soil, 1/3 Original Soil, 1/3 Composted Manure/Humus and set the plants about 1-2" above the surrounding soil. I used a soil conditioner (Structure) from Earl May as well as their Plant Start Fert (3-10-3 with rooting hormone and B1). Ive been watering them about every 4-5 days and check the soil every other day for moisture. Does this sound about right for a good protocol?

3. One last thing. I planted two PJM rhododendrons somewhat near but above the three hydrangeas in the same flower bed. Ive read where aluminum sulfate is bad for the rhodies. Will i still be ok watering the AlSO4 into my hydrangeas or should i find an alternative? Since the hydrangeas are below the rhodies it shouldnt run off into them.

Thanks so much and hopefully i will get some pics up soon!