I couldn't find an appropriate GW discussion for Clivia miniata, I know Clivias are related so, I thought I would see if any of you might be able to help.

We have a shade spot that gets a bit of morning sun. Our Clivias, all mature, undesturbed roots, do well and bloom for a month or more in spring. However, there is a tendancy for the leaf tips to yellow. It looks burned, however, only a bit of filtered morning sun gets into the bed. This occurs almost all year. We have tried different watering schedules with no results. Any ideas welcome