Answer: Banana plants are perennial herbs. They are the tallest and the largest of the perennial herbs. Their roots are fibrous. The larger the plant, the larger the root system. For even a large banana plant, the root system will be about 3 cubic feet. I don't think the roots are strong enough to damage a concrete wall or pad. If you are concerned, you can plan to dig the plant every 3-4 years and divide it to keep the root system small, or you can plant in a 5-gallon bucket (drill lots of holes in the bottom and sides for good drainage). This will contain the roots and every 4-5 years you can pull the plant out of the bucket and divide it, then replant.
Best wishes with your garden!
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