Hibiscus Fertilizer & Too Much Water

Fertilizer Needs

• In order to produce lush green foliage, your hibiscus needs nitrogen. However, instead of turning leaves green, too much nitrogen will turn the leaves brown -- a reaction called fertilizer burn. Also, although phosphorus is often applied to flowering plants to improve bloom yields, hibiscus cannot tolerate large doses of phosphorus. The nutrient powerhouse for hibiscus is potassium. A potassium-rich fertilizer applied regularly will keep your hibiscus filled with flowers.

Application

• Hibiscus plants are heavy feeders, especially while blooming, but they are sensitive to over-feeding. Apply fertilizer frequently, about every two to three weeks, but at half the strength recommended on the label. A 17-5-24 fertilizer that is heavy on potassium but light on phosphorus is ideal; a balanced 20-20-20 or 10-10-10 fertilizer is also sufficient. In addition to the yellowed leaves and poor flowering that indicate nutrient deficiencies, watch for cupping or puckering in new leaves. These symptoms point to a boron deficiency. Switch to a fertilizer that contains trace amounts of boron if necessary.

Water

• Plant hibiscus in soil that drains well but retains some moisture. Hibiscus is sensitive to environmental changes and prefers soil that stays evenly wet. If conditions are too dry, the hibiscus will wilt, drop leaves and eventually die. Too much water inhibits the roots' ability to absorb nutrients from the soil, turning the leaves yellow and resembling a fertilizer deficiency.

Environmental Concerns

• Too much fertilizer or too much water can harm your hibiscus plants. Too much fertilizer combined with too much water not only harms your hibiscus plants but may harm your environment as well. Excess fertilizer not worked into the soil run off with the excess water into local waterways where the nutrient boost encourages rapid algae growth. The resulting algal bloom suffocates the resident aquatic life. Excessive watering also leaches excessive fertilizer away from your plants down into the groundwater, potentially contaminating the local water supply.