This wonder will have a radius around it where all Gold Mines and Fruit Trees will be affected by the attributes. So make sure you place them nearby.
If you prefer having both Food and Gold, then this wonder will be beneficial for you. Unlike the Pyramids and Stonehenge, which can only provide a boost to one resource, this wonder gives a boost to both.
Another useful attribute about the Hanging Gardens is that since regeneration time is 20% faster it means more chances to harvest for Cider and Metal. These two trade goods are essential for the powerful Heavy Cavalry and ElephantMercenaries, and can be good for a consistent Armor Blessing.
It can be more effective by researching Pottery completely.
"The Hanging Gardens of Babylon were constructed by King Nebuchadnezzar, according to legend, as a gift to his wife, Amytis of Medes. Living in the flat desert terrain of Babylon, Amytis pined for the green mountains of her home, and Nebuchadnezzar built the Hanging Gardens to comfort her. According to the writers of the day, the Gardens were an astonishing sight, a series of terraces on huge pillars, covered with vibrant green plants and trees. Babylon being an arid desert with little rainfall, water had to be constantly drawn from the Euphrates river and moved to the top of the structure by ingenious bucket chains powered by slaves. The fate of the Gardens is unknown - some archaeologists speculate that it was destroyed in an earthquake in the 2nd century BCE."