The Citrus Lemon Lemon tree is native to Asia. The Lemon Tree is not completely hardy. During a period of frost, we recommend bringing the plant indoors or wrapping it. The Citrus Lemon is an easy outdoor plant to take care of. Just make sure you are aware of the proper care. The soil of the Citrus should always be slightly moist. Its water requirements will be higher in summer than in winter. The Citrus Lemon is used to a lot of sunlight and it needs this to develop properly. In the winter months it is important to use a tree cover or even bring the citrus inside for a while in case of extreme frost. A spot behind a south-facing window would be perfect in this case.