Perdita comes to them just as the ferry is leaving with a bunch of wild flowers she has picked for Janey - they are the ones their father had been searching for, so it seems they might return to the island another time so that Perdita can show him where they grow.
As the ferry is leaving with a load of wild flowers Perdita has picked for Janey, it seems like they may go back to the island again to see her father and learn about the wildflowers he was searching for.