Why doesn't the Christmas tree grow new leaves?

Insufficient sunshine, too much water and too little water may cause defoliation. I like warm, humid and sunny environment, and I like light and shade. After entering summer, I like warm and hot potted plants, so I can plant them in the shade or under the sunshade. The effect is very good. I often spray water on the leaves. Watering once a week, timely fertilization would rather be less than more. Especially after the heavy rain, check the flowerpot in time, and if there is water in the flowerpot, dump it as soon as possible.