Its the same reason why tree leaves change color in the autumn.


"Shirley Hill" wrote in message
...
Does anyone know why some of my geranium leaves are bright red? For the
last
two winters I have had them in an unheated conservatory where they have
been
fine, apart from the red leaves, which seems to gradually spread over the
whole plant and those nearby. Perhaps it is rust? They flower and seem to
thrive through the season once the warm weather arrives.