You're very fortunate that the center is still green. A couple years ago my collection was flooded out. That resulted in many leaves being scattered; plants up rooted and ID's being lost; and a lot of plants experiencing that black crown pheomenon (death). Had to replace nearly every plant in the collection. Now I keep my pings under a table or chair, where they get dappled sunlight and very little direct rain. They still color up but are removed from the environmental disasters.