Tu BiShvat, called the "New Year of the Trees," falls at a seemingly incongruous time of year.
Tu BiShvat is a minor festival whose provenance dates only to the time of the Second Temple. However, the kabbalists who clustered around the great fifteenth-century mystic Isaac Luria of Safed placed great weight on the holiday, creating new festivities, gatherings at which hymns were sung, fruit (particularly carob) was eaten, and four cups of wine were taken (as in the Passover seder).
One favorite dish of the Ashkenazim that survived the move from the shtetl to North America was the hearty mushroom-potato-barley soup called krupnick.
Judaism is filled with ritualized counting. From the seven ordered days of creation, to the repetition of forty throughout the Tanach (Hebrew Bible), to God's exhortation to Abraham to "count the stars, if you can count them…" Currently, we are in the midst of counting the Omer, the days from Passover to Shavuot.
What makes this holiday a favorite among secular Israelis, while it is almost forgotten by Jewish kids in the Diaspora?