Tu Bishvat (Tu B’Shevat), also called “Rosh HaShanah La’Ilanot” (New Year of the Trees) is kind of like a birthday for all trees. Trees planted before this day, even by one day, will turn a year older on Tu Bishvat. Traditionally fruit from trees may not be eaten for the first four years, so the age is important.
Customs include planting trees and eating fruit.
In the 16th century, the kabbalist Rabbi Yitzchak Luria of Safed developed a Tu Bishvat seder. The fruits and trees of Israel were given symbolic meaning. Eating ten specific fruits and drinking four cups of wine in a specific order while reciting blessings would bring people and the world closer to spiritual perfection.
Tu Bishvat occurs on the 15th day of the Hebrew month of Shevat.