My U. longifolia has leaves nearly a foot long, so don't be surprised if yours continue to grow considerably larger, it just takes time!
They do best for me in deep live moss, but with a lot of water at the base. *The plant doesn't have a dormancy, it continues to grow year round. *I suspect flowering is encouraged by compact stolons, so I dont divide mine too often. *Mine flowered in the spring after a cold spell which may or may not have had an effect.
The browning of the leaves is likely fungal in origin, and may be prevented by increasing the air circulation.
As an aside in the interests of education note the second half of the latin binomial is never capitalized: hence U. longifolia, or P. gracilis. I want you guys to look good :-)
Good growing all!