I think that bacteria are intrinsically better-suited to such environments - by default, there really isn't a "metal-cycle" in the same way as a "water cycle" to supply the raw ingredients.
But plants like this would be amazing. You could have junkyard-plants that grow in caves filled with rusty cars and turn them into...tomatoes or something. And heaps of rust.
You still need sugar. Ultimately, your plants need carbon, hydrogen, and oxygen. The exotic elements seem to come in along with one of those three elements.
So to answer the question about environment:
- A warm environment to mix the required materials (and energy to start the reactions)
- An environment that can move the materials to where the plant needs them, naturally. This implies a high-density environment.
- The waste also needs to be removed. Living in a pile of sulfur really isn't that pleasant. Terrestrial plants produce gases as the byproduct of their reactions, which are moved away from the plant by nature. Plants that produce piles of rust or sulfur will need a similar mechanism to keep the area clean.
- A steady supply of whatever materials they need is helpful
- A supply of water or air to bring in the H2O, CO2, or whatever hydrocarbon source is needed.
The most logical place to find these things is an aquatic environment. Maybe a hot spring or volcano...oh wait, what about a hydrothermal vent?
But it's also possible that the roles could be reversed - the "leaves" gather the materials, but chemosynthesis and waste production occurs in the roots, where it is carried away by ground water. In that case, you'd need some noxious metallic gas floating around, like maybe next to a volcano.
Finally, if all the need materials are available in the ground, you might see very spidery root systems, with only minimal structures to support flowers/fruits above ground for reproduction.
In any case, not somewhere readily habitable by humans.
What would the plants look like? I think you'd still have leaf structures, but they'd be more mesh than solid material, with lots of frills to grab the (fill in element here). Roots would probably be similar.
Plants would not be green. Most likely you'd see rust-colors, and the plants would "blanch" when they run low on materials.
Presumably there would be an ecosystem that would use the plant waste.