Secondary flowering regulation method for verbena bonariensis

The invention provides a secondary flowering regulation method for verbena bonariensis. The method includes the steps: reducing the water content of soil before the verbena bonariensis starts producing seeds and flowering number is decreased; pruning away all inflorescences; watering the verbena bonariensis once every 3 days; sequentially applying urea and phosphorus and potassium compound fertilizers; spraying gibberellic acid water solution 7-10 days after pruning; spraying daminozide water solution to leaf surfaces after sprouting; starting secondary flowering 20-30 days after pruning, andprolonging a flowering phase to the middle of November in the same year. According to the method, the water content of the soil is reduced after the verbena bonariensis produces the seeds, reproductive growth of plants is reduced, all the inflorescences are pruned away, nutrients are no longer consumed by upper seeds and florets, the gibberellic acid water solution is sprayed to promote nutritional growth of the verbena b