I have no clue what your weed is.
For what ever it is worth. If you want a mango, why not start with a grafted tree that will actually bear edible fruit?
I'm in the north, you are in California, I don't know if you would be able to keep them outdoors year round or not. For me, if I were to try one, they would have to spend 6 months a year indoors.
I have noticed there are half a dozen or more varieties of mango that are selected to be
'condo size' mango. At least 3 of the varieties on the list in this link are noted as being able to grow and fruit in containers and be maintained under 6 feet.
http://www.tropicalfruitnursery.com/mango/condo.shtml
And grafted trees should start fruiting within a few years if grown well.
Of course a 6 foot mango tree in a 20 gallon pot is not usually what we would think of as bonsai. In fact if you want them to have fruit, you should not prune they way you would for shaping a bonsai. One would have to be very careful to not prune below the graft, and not allow suckers from the rootstock to sprout.
But if one felt creative, perhaps you could train an attractive fruit tree, just don't call it bonsai, because you will really never be able to get the scale and proportions needed to create the image. You can have a nice container grown patio tree. Nothing wrong with getting artistic with your patio trees. I encourage you to try.
If you want bonsai with edible fruit, and don't want the 30 year process rockm described to create them; look to trees with smaller fruit. There are a few on the main list in the link above. Cherries come to my mind, if your winters are cold enough, eugenia & jabotacaba & kumquats and other citrus for more tropical options. The choices are many, key is to look for smaller fruit say maybe under 2 inches in diameter.
RockM was telling you the truth about the time it takes to create what you described. A noble goal, and if you want to you should try. But it will take time.
