I'm plant sitting for a neighbor and this morning I watered her 3 plants about 6:30 and they were fine. It has reached between 101-106 degrees(I have two digital outdoor thermometer and they differ from hour to hour depending on the sun exposure.) I just went to check the plants, they have been in the shade all along..but one looks like it has croaked. I watered it and hopefully it will bounce back..If it doesn't, I don't think there is anything more that I can do unless I were to repot it but figured that might be adding more stress to the plant. I recall a conversation on one of the forums about the soil/potting mixes that some plants are planted in.

I have found most annuals slow down duering really hot weather.
Keep checking it and watering.Impatiens are juicey and need it. Mine usually bounce back i late Aigust when the cooler temps and more steady rains come. We have had them last until November.

Wll, I think I am out of the hot water! I watered them again mid afternoon after I posted my message, bottom watered it that time and in a few hours checked on it again and it had bounced back. I am going to suggest that she might want to consider repotting it in some good soil because I think it might be in some of that soiless potting mix that the grower potted it in. It can also be a different variety than the other impatient plant. She could have purchased them from different garden centers/nurseries too..may have come from different growers.. The neighbor should be back by Thursday and I'll be glad to turn her flowers over to her but she knows its been 100 degrees plus here as I feel sure she has been checking in with her church office(She is a Pastor)

Are you aware of the new disease wiping out Impatiens?

The plants are not mine; I was just taking care of them while she was out of town on business. To be honest, I don't think she knows much about plants. I will remind her that she doesn't have to water the Christmas Cactus very often and to let it dry out before she waters it again. I've watered it once in 2 weeks and it is still a bit damp..Looks like it needs repotting. The plant belonged to previous renter who died last year. I will mention it to the son of the deceased..let him repot it. He told her she could set it outside back in June but we've been having 100 plus temps for last few weeks..We had a break in temps for two days but today it is almost 90 again. But 90 is better than 102, 104, and 107..

When we lived in our former home, I bought New Guinea impatients one year for under a cherry tree and they didn't do well. The ones that did the best were the Dazzler impatients and you don't find them anymore. I haven't seen them in the garden centers for years.