I ordered a Stellar Geranium from a nursery. When it came it was a very small plant, never the less, the plant stayed alive through the summer. In the fall I brought it into the greenhouse where it lost one leaf after the other. Is this a difficult variety to grow? There is only one stalk with one leaf on it left. I don't want it to die. What can I do to keep it alive? I water sparingly. The plant has been in the sun - but not too hot.