To encourage more flowers, use a high-phosphorus fertilizer (the middle number in the NPK ratio) during the growing season. Adequate sunlight is crucial for flower production, so ensure your Plumeria receives at least 6-8 hours of direct sunlight daily. Avoid over-fertilizing or providing excessive nitrogen, as it may result in lush foliage at the expense of flower production. Consistent and proper care, including watering and pruning, can also contribute to increased flower production in Plumeria.