I bought a Lily of the Nile. Planted, most the day sun, part shade (evening), and mulched the plant. Was doing great. 3 months later it started to get mushy and rot at the roots and base of the plant. So I thought there was a chance I over watered. I bought another and removed the mushy old one. I planted in the same spot as the old one but built the plant up more with dirt so water would definitely drain around it and off the plant. 1 1/2 months later it's mushy and rotting. I watered around the plant and never soaked it. I didn't want to loose this plant like the firt one, I love it. There is no drainage near by. It's located next to my sidewalk. Anyone know what I could be doing wrong? Ever happen to you?