Bougainvillea is a tropical plant known for its vibrant bracts and vigorous growth. From a plant’s perspective, its nutritional requirements are influenced by its natural habitat—regions with well-drained soil and abundant sunlight. Bougainvillea thrives when provided with a balanced mix of macronutrients (nitrogen, phosphorus, potassium) and micronutrients (iron, magnesium, zinc). However, excessive nitrogen can promote leafy growth at the expense of blooms, so a fertilizer with a higher phosphorus content is often preferred to encourage flowering.
Bougainvillea responds well to specific fertilizer formulations. Here are the most effective types:
Slow-release granular fertilizers, such as those with an NPK ratio of 6-8-10 or 10-10-10, provide a steady supply of nutrients. These are ideal for Bougainvillea because they prevent nutrient leaching and reduce the risk of over-fertilization, which can harm the plant’s root system.
Water-soluble fertilizers, like a 20-20-20 or 15-30-15 blend, are quickly absorbed by Bougainvillea. These are particularly useful during the active growing season (spring and summer) when the plant requires immediate nutrients to support blooming. However, they require more frequent application—typically every 2–4 weeks.
Organic options, such as compost, worm castings, or fish emulsion, improve soil structure while providing nutrients. Bougainvillea benefits from organic matter, which enhances microbial activity and root health. Bone meal (high in phosphorus) is especially useful for promoting vibrant blooms.
Bougainvillea’s growth and flowering depend on specific nutrients:
Phosphorus is critical for flower production. A deficiency can lead to poor blooming, while an adequate supply ensures vibrant bracts. Fertilizers with a higher middle number (e.g., 10-30-10) are ideal during the flowering phase.
Potassium strengthens Bougainvillea’s resistance to diseases and stress. It also aids in water regulation and nutrient transport, ensuring healthy growth. A balanced potassium level (e.g., 10-10-10) supports overall plant vigor.
Iron and magnesium are essential for chlorophyll production, preventing yellowing leaves (chlorosis). Chelated iron supplements or Epsom salt (magnesium sulfate) can address deficiencies, especially in alkaline soils.
Bougainvillea’s fertilization needs vary by season:
During active growth, apply a balanced fertilizer every 4–6 weeks. For water-soluble options, dilute to half-strength to avoid salt buildup in the soil.
Reduce fertilization in cooler months as Bougainvillea’s growth slows. A light application of organic compost or a slow-release fertilizer in early fall prepares the plant for dormancy.
Bougainvillea is sensitive to over-fertilization. Excessive nitrogen leads to lush foliage but fewer blooms. Always follow label instructions and avoid fertilizing drought-stressed plants, as this can cause root burn. Additionally, ensure the soil is well-drained to prevent nutrient lockout.
