Cultivation method for planting bougainvillea speetabilis in open field

The invention discloses a cultivation method for planting bougainvillea speetabilis in an open field. The method comprises the following steps: selecting a high-terrain dry open field which is open around and has sufficient sunlight; soil which is loose, breathable and good in drainage performance is selected; mixed soil is used as flower soil during planting; after the bougainvillea speetabilis in the open field is planted, watering thoroughly; spraying the trunks for multiple times every day to moisturize the trunks and increase the environmental humidity; in about 2 months after the bougainvillea speetabilis in the open field survives, the work of promoting blooming can be carried out; the bougainvillea speetabilis has particularly strong germination power under the open field condition; when the branches grow to about 30 centimeters, bud combing can be carried out for the first time; dense buds and adventitious buds are erased for the first time; when a part of new buds of the bougainvillea speetabilis gr