Answer: The secret to all-season bloom of Bougainvillea is not so much in feeding, but in pinching the tips of the stems back to produce new flowering wood. Pinch back throughout the spring and summer seasons and you'll have new bracts showing as long as the plant is putting out new growth.
To keep Bougainvillea thriving, most sources recommend feeding once in the spring and once in mid-summer. Your method of a dilute liquid fertilizer at each watering is acceptable for container grown plants, so continue the practice!
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