Red Geranium turning to green

[Mallika Jay]

My neighbour's red geranium flowers are turning to green. Now the flowers look like Hydrengias.Even the new leaves becoming smaller than usual. Any one for advise please.

[imafan26]

My guess is that it might be from either being too cold or the pH being out of the preferred range of pH 6.5. Usually, the leaves turn red from cold or pH changes and the colors can change in brightness and hue but sometimes sports just happen.