Hanging Garden of Babylon

Origin
The Hanging Gardens of Babylon is one of the Seven Ancient Wonders of the World. It is the only one whose location or even existence has not been fully confirmed. According to legend, the Babylonian King Nebuchadnezzar II built it for his homesick wife, who missed the green fields and gardens of her homeland.

Effects
A small potted unidentified bush that, when planted, grows into a massive complex of various flowers, trees and other plants. Growth is slow but exponential and will gradually terraform the area into tiers of foliage. Once the garden is large enough, it will begin to "grow" a city around it made of clay and limestone. Uprooting the original plant will cause the "grown" city and other plants to quickly break down and vanish, but geographical changes will remain.