The vital staining properties of rose cultures (Rosa cv Paul's Scarlet) of increasing age were compared with their ability to be subcultured. At 4-day intervals beginning on day 14, after cell division and expansion had stopped, cells were stained separately with Evans blue, fluorescein diacetate, and phenosafranine. The degree to which parent cultures stained with each of these dyes was compared to the dry weight of their subcultures harvested after 9 and 21 days of growth.Staining with either Evans blue or fluorescein diacetate was demonstrated to be a good means of establishing when senescing cells died. However, the staining properties of aging cultures did not correlate well with their ability to be subcultured, because an increasing proportion of the living cells appeared to lose their ability to divide as senescence progressed.