Looks like the difference between juvenile and adult leaves. A change Light levels, watering, temps or anything can cause a plant to "switch" over to a mature state even after years of steady growth. This is called "Ontogeny" Think of it as similar to a person growing up, A child looks different at 5, then at 10, at 15 and so on. Facial feature change with maturity. Many plant species do the same thing. I don't know the species of your plant (I'm sure someone here will, Looks like a type of aroid like a philodendron, monstera or anthurium, maybe a syngonium. But I could be wrong. Anyways, Lets take monstera as an example, A seed hits the ground and takes root, once leaves develop it starts to grow along the ground towards the deepest shade close to it which generally means the biggest tree it can climb up, As it climbs up the tree the light levels change among other things like air circulation and temperature and the leaves not only get bigger but the also change shape. Many species of plant do this, aroid especially so. Danny

Living here 29 yrs. have always had hibiscus and studied them, yes, the cold snap will create yellow leaves, but most important is they do not like wet feet, in other words a light watering once a week in our now dry season is just fine, in our rainy season, mine are under the over hang of the house, plus wehave gutter all around, so they do not drown. my wallpaper on my screen is this shot of my pink..notice a couple yellow leaves this is normal:

Rosco_P, First, I love the name you used! Second, you are welcome. I really enjoyed taking the class it did help explain much to me as well regarding coloration of plants. And now I can pass on what I have learned.

Morningluna, Welcome to being a hibiscus owner! I must warn you, they are addictive! Your plant is gorgeous! No wonder you bought it! How long have you had it? It will grow really large this summer being planted out in the ground. I grew a red one in the ground last summer and it grew 8 feet tall! If you want to bring it in in September, just pot it up. If you don't want it in the house over the winter, you can just let it die over the winter and buy another one for next year and plant that one outside. They love humidity and sunlight, and they love the hose on their foilage when it gets real hot. This also keeps the bugs under control. I think tropical hibs are my favorite plants! I love gardenias, (which I try to grow every year), but tropical hibs are the best! GOod Luck!