I'm liking Eric's idea too.
You might even have them not be really plants, but simply be 'food" that is plopped into the sim, without any abilities at all. They wouldn't reproduce, see, or do anything.
After all, if you're after reproducing veggies, you're probably after evolution, mutation, and DNA.
While I'm slashing concepts, they could be made of a substance that responds as nrg if it's hit with -1 shots and responds as body if it's hit with -6 shots, so bots don't have to learn to use particular shots.
They're just used as emergency and boot strapping food sources.
Also, you could add a cost field that charges bots nrg every cycle that their eyes are turned on. This would encourage bots to remain blind if they don't use their eyes.