Bougainvillea Flower Fertilizer. Do this during the growing season if you want it to work well. Use a high-potash fertilizer such as a hibiscus or tomato fertilizer during spring and summer.
Here in this video I have revealed how I fertilize my B. Feed your bougainvillea with a fertilizer containing nitrogen and phosphate once a month during the bloomer period ie from early spring to mid-summer. For bougainvillea vines growing in the ground use half a cup of granular fertilizer per 4 feet in height and lightly scratch it into the soil surface using a trowel or a hand cultivator.
Mix 1 tablespoon fertilizer with 1 gallon of water and water the plants soil.
Feed your bougainvillea with a fertilizer containing nitrogen and phosphate once a month during the bloomer period ie from early spring to mid-summer. Mix 1 tablespoon fertilizer with 1 gallon of water and water the plants soil. With four sources of nitrogen to meet the nutrient needs of a heavy feeding plant Epsom salt and potassium to encourage blooms as well as extra calcium magnesium and iron. Feed bougainvillea vines that grow in containers once per month with a water-soluble all-purpose 5-5-5 fertilizer.