We live in the desert in New Mexico, and have 6-7 large pampa grass clumps around our house. Some have become black in the middle and are only growing on the edges, and there not very strongly. I have never trimed them. Any suggestion on how to revitalize the struggling ones. Our temps range from 100F to 0F.
I had the same problem with my maiden grass. I dug it up, split it up and moved it to a new place and all of the clumps have come back vigorously. I would definetly try this and cut off the parts that look dead. Do Not, I repeat do not fertilize. Ornamental grasses are known for growing in the worst soils, but do plant in full sun. I know it sounds crazy but the most depleted soil will produce the best results. I would do this asap before they lose all energy and die completely. And I think it does best if you trim it down right before new growth appears or burn it down. Leave at least 6 inches of the clump above ground. This will also help to keep it upright and strong. I hope this helps.
Only burn it down if it is at a safe distance from the house and other plants! If it can be done safely, it is a very good way of rejuvenating it though.
