Plant pigments are extremely variable. It's quite possible the weather played a role in the perceived color shift. If you give them long enough, they will probably change again back toward the tones you prefer. Kim

OK, thanks. Would that hydrangea food help? You know, the one that keeps hydrangeas blue?
My dream is to fill a huge 20 inch blue pot I have with a white Iceberg. I love the clean color and the honey fragrance. Against the medium blue pot it'll be beautiful.

Fertilizer which turns hydrangeas blue are generally higher in nitrogen. Nitrogen does a number of things to all plants, but the main function is to stimulate growth. Too high nitrogen can burn the roots, particularly in a pot where there is limited soil and usually higher soil temperatures than in the ground. That type of fertilizer may be too high in nitrogen and it may stimulate the plant to grow more and flower less. I would use either an all purpose, "bud and bloom", or a "tomato type", which is the usual rose and flower food. The key to fertilizing potted plants is to water very well several hours before feeding, then use no more than the instructions suggest. It's actually safer to use quite a bit less than the instructions suggest. You can always add more, or feed more frequently. It's virtually impossible to remove too much. Kim

Oh, I didn't know about this. Thanks. So maybe they will bloom white on their own again. I hope so !

Iceberg is a creamy white. It may become more white in the hotter weather. But it's not a pure white rose.

Mine is pretty white here. Set next to ivory 'French Lace' there is a considerable difference. The one that is really icy snow white is Aimee Vibert, but it is only a little whiter than Iceberg. It seems like 'Madame Hardy' is another really icy white, but it blooms so rarely here I haven't seen it recently and can't remember for sure. 'Snowbird' is creamy ivory as is 'Kaiserin Auguste Viktoria'. 'Fabulous' is pretty white. 'Fair Bianca' is very white but it's such a problem-plagued cultivar...'Glamis Castle' is very white also, whiter than Iceberg. 'Bolero' will often have a touch of pink.

Last month during the spring flush I gathered one of every single white or ivory rose in the garden and arrayed them all and took a photo of the range of whites. Then I did some gardening and forgot all about everything else and the flowers dried up. The next day when I went to look at the photos I realized the stupid memory card wasn't in the camera when I took the pictures. Boy was I mad. Next flush...maybe I'll get a photo.

Mine are paper white. The whites of your eyes white. Clean icy white. That's why I love them. Hopefully they'll be back !