well here we go... a plant that is a flowering female be 20 years old... NO... that was a total myth... lie , bullshit lol...
now a mother plant being 20 years old yes...
but...
you can keep a mother plant forever , the only thing after 20 years lol your looking at one huge ass pot/container... you can take cuttings and keep a mother plant forever the only thing with this is the roots will still grow and will eventually become root bound ever x many days / months and will have to be transplanted...
there is no mj that ever was/ever will be 500$ a gram
edit... well I should take that back.. you can have a flowering female be 20 years old.. she would of had to of been a mother plant for 19 years and 9-10 months then flowered out lol ... so ya you can have a 20 year old plant that buds.. but as far as potency and price... haha 500 a gram come on...