Using black elephant ear in a container

Hi. We live in Courtenay, Vancouver Island and I was looking to make some unusual planters for the front. I have tall planter containers and I was going to copy a gardening magazine idea ( maybe not a good idea) by putting a smaller pot in the planter with black elephant ear plant (colocasia esculenta), Fuchs and impatiens, and plectranthus. I know this will be a shade planter but I am wondering if someone has some good ideas on how to plant it up. All the plants have the same shade requirements BUT the black elephant ear should be kept very wet unlike the other plants. I have a special soil mix ( with shredded coconut) to retain moisture for a smaller pot which will contain the elephant ear which would sit in the pot that sits in this tall container. Then I thought the other plants could fit around this smaller pot in regular potting soil. Will this be enough to keep the elephant ear wet. Someone suggested to fit the elephant ear pot with a saucer put this in the container, fill with regular potting soil and the other plants. That way when I water that small pot holds some water from escaping. Does this make sense???

 

Yes, I think that might work. A bit fussy in prep perhaps!