As of now, plantations aren't existing anymore. Crops can now be planted anywhere suitable (on patches of grass).
Plantations are located throughout the map where citizens can plant seeds to grow a range of Drugs and Olives you must be within the blue circle to grow any type of crop.
Plantations are blue circles on the map screen there are 5 of them throughout the map.
(Example of plantation on map)
The locations of plantations change when the server restarts
CLPD will be looking for plantations as well for citizens who are growing drugs, They will have to get this information for the Bar tender at Club 7.