(This probably will spoil you if you haven't seen all of Trigun.)
The weapons that Vash and Knives manifest are called "Angel Arms". This is likely due to the "wings" that appear on them when they are fully present. (This is much more visible in the manga than the anime.) The female "plants" in the bulbs also seem to have wings. There's very little on where the plants came from in the anime, only that they are part of the "Pandora's Box given to humanity by God" and what is said in the Project SEEDS episode about how they were developed on Earth.
Do you think this is a commentary on how man uses God to suit his needs, instead of allowing himself to be used by God? The plants in their bulbs are beautiful, sensitive creatures, as evidenced in the episodes where Vash speaks to them. Yet they are prisoners of humanity, forced to be sucked dry of energy, in the same way humans will beg God for favors and blessings but not bother to keep His commands.
And that's not even touching on Vash's obvious Christ parallels...
Now here's a thought. If Vash is Christ, who is Wolfwood? I would say Peter, for the denial, the martyrdom, and Peter's position as a pharisee is roughly equivalent to Wolfwood's in his "church".