Light (0.089–0.12 g cm−3), superabsorbent (84–99 g water/1 g aerogel), and highly flame retardant non‐crosslinked cellulose aerogel (CA) and crosslinked cellulose aerogel (CL‐CA) have been successfully produced from pruning waste of blueberry tree. The prepared aerogels with three dimensional porous structure have a remarkably thermal stability and flame retardant performance, which totally burned after 136–200 s. Besides, CA and CL‐CA have an important Brunauer–Emmet–Teller surface area, which are 348 and 275 m2 g−1, respectively. The concepts of this study are simple and bio‐wastes are easily available and sustainable at low cost, and therefore, the current process is appropriate for industrial scale production and has a significant potential in the future of green materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45315.