You are right, it was only passively mentioned in the bible. The details are found in other documentation but the bible does speak about the tree in reference to Semiramis. It has been several years since I talked about it in detail with someone.
The tree scripture: Jeremiah 10:2-5
"Thus saith the Lord, Learn not the way of the heathen, and be not dismayed at the signs of heaven; for the heathen are dismayed at them. For the customs of the people are vain: for one cutteth a tree out of the forest, the work of the hands of the workman, with the axe. They deck it with silver and with gold; they fasten it with nails and with hammers, that it move not. They are upright as the palm tree, but speak not: they must needs be borne, because they cannot go. Be not afraid of them; for they cannot do evil, neither also is it in them to do good."
This is just a briefing on it:
What the Bible says about Nimrod