A star jasmine (Trachelospermum jasminoides), also called a confederate jasmine, is not a true member of the jasmine family, although it is a flowering vine like a true jasmine plant. If left to grow on its own, a star jasmine will get out of control and possibly choke out other nearby plants, making pruning a necessity. It is a tough plant and will recover from just about anything you do to it, but keep a few things in mind when pruning your star jasmine to keep it blooming for years.
Wait to give a star jasmine its annual pruning until after it is finished blooming, usually in the late spring or early summer. A star jasmine blooms on last year's branches. So if you prune in the early spring, you'll cut off this year's flowers. If you cut too late in the summer or fall, you'll prune off next year's flowers.
Prune to shape a star jasmine during this annual pruning using hedge or pruning shears, or hand clippers. A star jasmine is sometimes cut back to look like a hedge. Pruning also helps control growth so it will stay in a defined area. Typically, do not prune more than one-third of the bush, although if you do give it a hard pruning, it will grow back after a few growing seasons.
Cut off long, gangling branches or branches that are not growing in the direction you want them to grow at any time. Prune off damaged, broken and diseased branches at any time as well. Clip off the tips of growing branches if you want to encourage lateral growth.