The Jewish National Fund has compiled their Tu BiShvat programs, Divrei Torah, and Haggadot into one resource page. Here, you can find seders, lesson plans, and group activities to engage students in the New Year of the Trees. The resource also includes Divrei Torah from a diverse cast of rabbis, as well as Haggadot to enhance your seder.
JNF has Tu BiShvat programs for family learning (all-ages), middle school, and high school.