Native to subtropical parts of southern China and northern Southeast Asia, the star jasmine (Trachelospermum jasminoides) is so widely planted and associated with the American South that it's more commonly known as the Confederate jasmine. The glossy dark green leaves are mainly evergreen but drop away in very cold temperatures. The fragrant white, star-shaped flowers make this a spectacular but aggressive plant to grow on fences, walls, tree trunks or telephone poles. Grow Confederate jasmine outdoors in U.S. Department of Agriculture plant hardiness zones 7b through 12.
Confederate jasmine potentially grows 3 to 6 feet a year. Initially when first planted, this vine seems to sit dormant the first summer, barely adding any new stem length. Instead of leafy shoot growth, it is developing a broad, extensive root system. In the second year after planting, the growth rate increases a bit more and by the third spring after planting, Confederate jasmine reveals its robust and fast growth rate. By the end of summer, vining stems flop and cover an expansive garden area, prompting you prune it back.
Variegated selections of Confederate jasmine, such as cultivars "Variegatum" and "Tricolor," do not grow as fast as the fully green-leaved forms of this vine. Instead of adding 3 to 6 feet a year, variegated types may only add 1 to 2 feet per year. The presence of nongreen pigments in leaves lowers the amount of food manufactured by green chlorophyll pigments, thereby diminishing the growth rate. If you don't want as fast or aggressive a vine in your garden, choose a variegated Confederate jasmine, which is easier to prune and manage in smaller spaces.
Green-leaved Confederate jasmine vines will mature with a height of 25 to 35 feet long. If there is no vertical surface to climb, the stems will sprawl and clamber over everything in order to bask in sunlight. Pruning can control Confederate jasmine, but the regrow is always fast and aggressive. The best time to prune this vine is late spring to early summer, immediately after the main flowering display ends. In regions with long, frost-free growing seasons, such as in USDA zones 9 and warmer, prune in late winter. Flowers only arise from stems that are mature, at least six months old. Lots of white latex sap bleeds from Confederate jasmine stems.
All Confederate jasmine vines, regardless of cultivar, grow best and fastest in nonalkaline soils that are rich in organic matter, moist and well-drained. Planting this vine in hot, dry sand or compacted, unirrigated clay will stunt the growth, often making the plant look a bit sickly. Too little light can limit growth as well, and inhibits good flowering. For best performance, plant it in full to partial sun -- between 6 and 12 hours of sunlight daily.