I planted about 3 different types of crotons last year. These include the "corkscrew", "Oak Leaf" and what I refer to as the "regular" croton. All of these had very bright colors (especially the regular and oak leaf). I cut ALL of them down earlier this year and all have survived and have now produced new leaves. My problem is that regardless of the variety, ALL of the leaves are solid green. Yup, not even a hint of yellow, red or orange in any of them. I've watered them and fed them but now I'm just scratching my head. Can anyone help?