They were all over the island, or at least the base of the mountain as they don’t grow well higher up as it’s cooler up there.
They also need a lot of water and respond well to the ‘horizontal rain’ they have in La Palma. This is the permanent clouds that surround the mountain and are full of moisture. This moisture is soaked up the the vegetation, and the islanders have created irrigation tunnels from the top of the mountain down the bottom making La Palma extremely green.
I had never seen bananas growing before and didn’t realise what bonkers looking flowers they have at the bottom!