Perennials that thrive long without division are peonies, hosta, dayililies and most sedum groundcovers such as sedum 'Angelina' and hen's and chicks. Grasses such as Japanese Forest Grass, sedges and many of the miscanthus or Maiden Grass also go for years without needing dividing, but they may need to be cut back in early spring depending on the variety. Keep growing, Marianne Binetti