Leaves not doing so well. Turning yellow. – Reddit Post

This is my (assumed) Hibiscus plant. I just found out what it was moments ago. Been at my house for years in ground. Never watered. Just a stick basically thatvwould put a pink flower once or twice a year. Got it potted and cared for and it took off. Many flowers. New shoots. Its great. But now the leaves seem pale and many are turning yellow. Is this normal? I have no idea how to care for this one. Should I be pruning or what?