Q. A few weeks ago I cut my ornamental pampas grass down, removing all last year’s dead growth. As the new growth is starting, I noticed a peculiar brown, circular pattern in the center that hasn't happened in the past. The new growth is coming along fine; nice and green, and a couple inches taller. Just nothing in the center.
|Brown Center of pruned pampas grass|
A. This brown center is common to many ornamental grasses as they get older. When the plant is very young and juvenile the entire plant is green, even the center.
As these plants get larger, they grow from outside shoots, or tillers, that make the plant larger in diameter. Each year this clump of grass gets larger and larger with the brown interior getting larger as well.
When these ornamental grasses get larger, the entire clump is dug up and divided into several smaller clumps. This propagation technique is called “division”. The brown portion of the plant is removed and the smaller plants are replanted or containerized and sold as a juvenile plants.
However, the new growth of your plant will cover up the dead interior and I don't think you will notice it anymore until you cut back again.