The seed doesn't do anything by itself and cannot be planted ( to the best of my knowledge), but rather it is a crafting material for imbuing. I believe it is used for HP/Mana/Stam regen.
As far as I can tell and from what I have read, harvesting the seeds from any plant that can produce seeds has a 5% chance of producing a seed of renewal rather than the regular seed it is supposed to produce. In other words, if you have twenty plants, by the time they've produced all their seeds, you should have around 8 seeds of renewal. Of course, that is an average, and I have gotten two in a row, yet also have harvested 60 plants and gotten none ( though the odds of getting none from the entire 8 seed load of 60 plants is very small).
Anyone who has access to the plant can get seeds, thus I presume anyone can get renewal seeds that can get seeds from the plant. You can set permissions for plants just like secure containers.
As far as I know the location the plant grows in has no bearing on the likelyhood of getting a seed of renewal.