I'd say remove the grass to get rid of competition and lay down a layer of mulch. Sometimes plants seem to stall after planting because they are spending energy to build root mass. Check the root ball. It could be dry and water repellent in which case regular light watering would have trouble to reach the plant's roots.

Hope this helps.

-Alex

I'd also get rid of the weeds and mulch. Agree with checking moisture conditions at root level.

Frequent waterings could be depleting the soil of nutrients causing leaves to yellow.

#3 for removing turf or whatever that is, and using mulch to retain moisture. You might be surprised at how tough a competitor turf can be. In trees, it absolutely outcompetes a young transplant where no mulch ring is installed and grass is allowed to grow right up to trunk. This ain't that but you get the idea.

Oh, and many Alocasias and Calocasias are supposed to have chartreuse foliage. Are you sure this isn't one such cultivar?

+oM

Put some black cow or other composted manure.