Hibiscus Leaves Turning Yellow

My hibiscus is planted in a whiskey barrel and looks like the leaves are droopy and yellow even though I water it. Also the flowers only last one day. What am I doing wrong? This is my first year for this plant and I received it from a friend. The other hibiscus plants I see in the ground look great.

Tropical hibiscus (Hibiscus rosa-sinensis) requires full sun to partial shade, moderate to very moist soil that is well-drained and regular feeding to grow and bloom profusely.

Yellow leaves are a sign of nitrogen deficiency. This can be remedied in a few ways. First add some slow release fertilizer or compost to the soil. Next you don’t want the soil to dry out completely, but it shouldn’t be swampy either. To achieve this balance water deeply, but perhaps less often. Allow just the top inch of the soil to dry between waterings and make sure that the soil in your barrel drains well.

If these steps don’t take care of the problem, then the soil in your barrel may be too alkaline, causing a micronutrient deficiency of iron and manganese. There are several ways you can correct this. You can use a foliar spray of micronutrients 2 or 3 times per year, add an ingredient to your soil that is acidic such as peat moss, or use sulfur powder to acidify your soil slightly. Organic mulch such as pine needles will help with this problem as well.

As far as the flowers lasting only one day – that’s the nature of the plant. A bloom will usually open in the morning and then wilt in the late afternoon, rarely lasting for more than 24 hours. The good news is there is usually another blossom right behind it.