I've been growing this Crepe Myrtle indoors for about 5 months. Just noticed this morning that the leaves are wilting. I have a few theories, but would love some advice. Theory one is that the pot isn't tall enough----do the roots need more vertical space to grow? My other theory is that maybe it's just been under-watered recently. I wasn't expecting it to get so big, but I'm really hoping I can keep it healthy. Thanks for any advice!