Method for promoting secondary blooming of lilac

The invention provides a method for promoting secondary blooming of lilac. The method comprises the following steps: step 1, application of a base fertilizer in autumn: applying an organic fertilizer to the base part of a plant at the end of September of the year before treatment, adopting a hole application or furrow application method, and performing irrigation after the application; step 2, pruning: after the lilac blooms in April in spring, immediately cutting off residual flowers, and thinning and removing thin and weak branches; step 3, topdressing after blooming: applying an inorganic fertilizer at the beginning of May, then applying the inorganic fertilizer to the field once every half a month, immediately carrying out irrigation after fertilization, and continuously applying the inorganic fertilizer for three times; step 4, flower bud induction: from the beginning of June to the end of July, spraying a promoting and controlling agent to leaves once every 15 days, and conducting the spraying 4 times t