I have a geranium given to us by a friend. It does not seem to be growing. Earlier someone suggested that I not fertilize for awhile till the roots develop or the roots would develop shallowly. Now, its still not growing, but also the new leaves at the top are turning yellow. It receives regular watering and also it rained for an entire week. I live in zone 11 and it has been prety hot and humid with temps going into 90's. Could this be a cause of the slow growth?