The reason why palms leave on Palm Sunday is commemorate Jesus's triumphal entry into Jerusalem, where the crowds wave palm branches and spread them on the ground which is a tradition that symbolizes joy, victory and also the arrival of a king and is now a symbol of the Christian faith.
At the end of the Bible, people from every nation raise palm branches to honor Jesus.
And Palm Sunday also commemorates the entrance of Christ into Jerusalem, during which palm branches were placed in his path, before his arrest on Holy Thursday and his crucifixion on Good Friday.
What the Bible says about a palm tree is that palm trees and most particularly the date palm trees are symbolic of righteousness, flourishing and even victory and is as seen in Psalm 92:12 and in the Gospels during Jesus's entry into Jerusalem.
The passage Psalm 92:12-14 famously compares the righteous to a palm tree, and states that "The righteous shall flourish like the palm tree and he shall grow like a cedar in Lebanon.
Those who are planted in the house of the LORD shall flourish in the courts of our God.
And they shall still bear fruit in old age, they shall be fresh and flourishing.