Water. They need a LOT more water than any instructions I've ever seen. I had so much trouble with mine, but I kept giving it more water. More and more and more water. I grow it in a container and I water it nearly every day. Generously. As long as I do that, it keeps growing and blooming. If I skip too long, it quits blooming and starts dropping leaves and, if I've waited too long, I have to submerge it for a while to get it moisture throughout. It can suck all the moisture out of the soil very quickly. I know it needs upsizing to a larger container because it has outgrown its current residence, but it's taken me about three years to learn to water it every time I walk by it. Early on I thought I'd lost it because it turned brown and growth was dying back.