In order to introduce the planting and cultivation of Bougainvillea spectabilis in Jianghan area, domesticate the varieties that can adapt to the climate of Jianghan plain, improve the market competitiveness of B. spectabilis and make it more widely popularized. A comparative experiment on overwintering cold resistance was carried out with six Bougainvillea varieties introduced from Yunnan, China. By comparing the freezing injury degree of B. spectabilis under indoor and outdoor environmental conditions and measuring the physiological indexes such as electrical conductivity, soluble sugar content, soluble protein content, catalase activity and peroxidase activity of its leaves. The experimental results revealed that: under the same management conditions, Yunnan Purple bougainvillea suffered the least degree of freezing damage and could successfully overwinter, while other varieties suffered more damage. The comprehensive evaluation shows that Yunnan Purple and Green Leaf Orange have strong cold resistance. Except for Yunnan Purple bougainvillea, which can survive the winter smoothly outdoors in Jianghan Plain, other varieties are difficult to survive.
