I have a dozen Pelagodoxa henryana that I planted around our farm. I am getting mixed results as this palm seems to need more potassium than it’s able to extract from our highly acidic volcanic Hawaiian soil. Mulching has definitely helped as it buffers the low (4.9-5.1) pH. But any suggestions on getting these guys going would be greatly appreciated. These seem to do better during our droughts which seems consistent with the theory that soil pH is the issue. Specimen below is in divided frond phase, which btw I find bizarre.

I don’t believe the palm pictured is Pelagodoxa Henryana. They should have entire leaves throughout their entire life cycle. They are only divided by wind or other environmental factors. 

I agree those don't look like Pelagodoxa. Here is what mine looked like at about that age. No particular issues with fertilizer.

I was surprised too by the divided pinnate leaves but I can assure you that the seedlings came from a mature specimen that was correctly identified in the seeds match the description as well. Most palm collectors who visit my garden see them and recognize them. I got curious about the split stage and browsed the web which resulted in the following explanation.:

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Yes, Pelagodoxa henryana, a rare monotypic palm species native to certain Pacific islands, does indeed exhibit an interesting leaf development pattern. Juvenile plants start with split, pinnate (divided) leaves, which is a characteristic of many palms. As the plant matures, the leaves become entire (undivided), forming the distinct, broad, entire leaves typical of mature Pelagodoxa henryana.