The methods and compositions described herein relate to producing, expanding, enriching, and/or maintaining hematopoietic stem cells ex vivo by treating the cells with an agent(s) that exhibits two or more activities selected from modulation of histone methylation; inhibition of TGFβ signaling; inhibition of p38 signaling; activation of canonical Wnt signaling; and modulation of histone acetylation. In some embodiments, the technology described herein relates to transplantation of hematopoietic stem cells.