"clippings" or "trimmings" is good.
(plural, so change "was" to "were" in your example sentence, of course)
These are general terms, but their meaning is clear in the context of someone's hair being cut. Their full description would include the word "hair" (i.e. "hair clippings") so we know they aren't grass, or newspaper articles. Viewing the answers here, I would say "clippings" is considered the best, but "trimmings" and "cuttings" would be clear, and even "shavings" if generated by an electric razor. As pointed out below, they are still "hair", so instead of the clippings, you might sweep up the hair or the pile of hair, or just the mess.