What Plants Do Not Grow Next To Ninebark Bush?

Question

I put a tomato plant and a flower plants in pots next to a nine bark bush and they died a week later, but the petunias are fine and thriving.

Answer 1

If they were in container, then the Ninebark didn't kill them. The toxicity happens at the soil level, and if they don't share the same soil, then something else killed your plants.

It will be hard to say what, without photos, and knowing the care that they received, and quite a bit of other information. I can say that your shrub did not kill them, though.