Tu B'Shevat is a minor holiday that is sometimes called the New Year for Trees. It comes at the very beginning of spring, when the rains are plentiful and the trees blossom in Israel (though in some parts of America there's still snow on the ground at this "springtime" celebration). The words "Tu B'Shevat" literally mean the 15th of the month of Shevat.
Today, many people mark this holiday by planting saplings and participating in a meal that evokes the Passover seder, where fruits, nuts, and wine or grape juice are on the menu. Besides the seder, many families spend Tu B'Shevat planting a tree, working in a garden, eating special fruit, or doing something else to show some love for trees and the earth.
Holiday description provided by Kveller.com.