The Jewish people are likened to a rose that gives off its fragrance when it is being cut. Hashem allowed us to suffer the pain of slavery in Mitzrayim (Egypt) so that we could give off a strong fragrance of emunah (faith) to last until the final redemption. When we look at something from an inner place, from our neshama (soul), everything becomes gold. On Tu B'Shevat, when everything appears to be dead, is when the sap begins to rise in the trees.