Winter jasmine plants are deciduous perennials. They are considered vines and belong to the olive family. Unlike most jasmines， this type is not fragrant， but， perhaps as a tradeoff， the plant's stems stay green in winter. Winter jasmine plants are moderate growers， native to China， and grown in USDA plant hardiness zones 6-10. Winter jasmine plants reach 4 feet in height with a width of 7 feet when unsupported. Supported， they can reach 15 feet in height. Its plentiful yellow blooms are about 1-inch wide. Blooming time is in late winter. The flowers appear prior to the leaves， which are quite tiny. This moderate-growing gem should be planted in the spring. While usually pest and disease-free， winter jasmine occasionally suffers from mealybugs and aphids. A good insecticidal soap should do the trick.