in the intervening 25 years ... how big did the trees around them get???

you already mention it is getting more shady ... did you run across a lot of tree roots??? ... water competition???

ken

Ken, there is almost no water competition and there were no tree roots. We were shocked to hear these had been put in so many years ago. The shrubs (boxwoods) around them were stunted, too, but we loosened the roots and pruned them last year and they're much healthier now. These four nandina, however, didn't improve.

The one out of the ground has no healthy roots visible. Try shaking the old potting soil off, replanting bare rooted or nearly so into the native soil, working that in around them so they are not sitting in pockets of air.

I think nandinas need good drainage. Also, voles can be a problem. I've had the entire root systems eaten by voles one year after using a lot of hardwood mulch around them in the Fall. I don't do heavy Fall mulch anymore!