How much rain can petunias survive in?
Certified GKH Gardening Expert
Like most plants, how well petunias will survive heavy rain depends on the soil type you have. If you have well-drained soil, they can survive a lot of rain. If you have poorly drained soil or soil that stays wet most of the time, the roots will drown with too much rain. Disease can also be a problem.
Planting in a raised bed with an open bottom is one option for dealing with this.