Welcome to the Nexus!
Did you take any psychedelics yet? Any interest in taking something before your trees are grown years from now?
Regarding plant sources, it depends where you are, climate and so on.. Check out this for some ideas:
wiki.dmt-nexus.me
wiki.dmt-nexus.me
I think most or all these plants are legal or illegal, depending if they can prove you had intent of consuming/extracting them for drugs. The point is that its impossible to enforce against every person with posession of any lifeform containing DMT because everybody would have to be arrested. So they take on priorities.
But if you have a garden of several different kinds of plants, and amongst them some dmt-containing plants, and you dont 'slip up' with some other silly mistake elsewhere (like announce to the world youre extracting your garden for drugs or sell dmt), you should never have any problems.
If I were you I would certainly get some acacia seeds, like acuminata, obtusifolia, etc. .Also growing good phalaris strains (aq1 and big medicine for DMT, turkey red for 5-meo-dmt), desmanthus, etc..Whatever you can get your hands on, go for it, the more the better. Grow grow grow, spread seeds around, let us know how it goes