A fiber aggregate having cellulose fibers as a principal component. The cellulose fibers have an average fiber diameter of about 25 microns or less, and may be clustered together. Per gram of fiber aggregate, the cellulose fibers may hold about 10-21 mL of an impregnating solution that has water as a principal component. The fiber aggregate may be included as part of a water retention agent for flowers and/or woody ornamental plants.
