This past summer I was lucky enough to get a crown of thorns tree from a neighbor who had to give it up due to her grandchildren and the risk of its sharp spikes. It did wonderfully outside over the summer, but when I brought it in it started losing leaves. I have it in the brightest spot in my house now (between a northwest facing and a southwest facing window) and it's still losing leaves yet still blooming. I water it once every few weeks and never let the soil get too wet. Is there something I'm doing wrong? Please help! I love this plant and need to get it through the winter!