Is There a Form of Ligustrum that Is Not Invasive?

Almost all privets (Ligustrum spp) can be invasive, since they produce berries whose seeds get sown far and wide via the birds who eat those fruits. Usually grown as hedges, the evergreens are so vigorous -- with hardiness varying according to type from U.S. Department of Agriculture plant hardiness zones 4 to 11 -- that they can crowd out less aggressive native plants. Fortunately, there is a sterile cultivar for USDA zones 6 to 10 that makes neither flowers nor berries. Ligustrum sinense "Sunshine" isn’t exactly an evergreen, though. It might more accurately be called an ever-yellow!

The "Sunshine" type of privet won't grow into a tall hedge quickly. Though it may eventually reach up to 6 feet in height and an equal width, it will take about 10 years to do so. Also, it is far from the traditional hedge color. The plant’s oval and glossy new leaves emerge chartreuse in the spring, but soon mature to yellow in full sun, picking up a hint of gold and orange in autumn. Only shrubs planted in the shade remain yellowish-green. Those bright leaves might be called the "Sunshine" privet’s blooms, since it makes no other!

How far apart you plant your "Sunshine" privets will depend on how tall you want your hedge. For an interesting low-growing barrier that can be interlocked with others in knot gardens, place them 2 feet apart. If you want a higher hedge or prefer to grow the privets as free-form shrubs, set them 4 to 6 feet apart. You’ll need to dig holes about twice the width of the containers, but 1 or 2 inches less than their depth so that the plants' crowns sit slightly higher than the surrounding soil level.

To make a formal hedge, wait until the plants fill the gaps between them. Then you can set up stakes beside them and run a string from stake to stake at the height you want the hedge to be, as a guide for your hedge shears or trimmer. Formal hedges are usually cut slightly narrower at the top than at the base, to allow sunlight to reach that base, and require trimming two or three times per year. When grown simply as a shrub rather than a hedge, this privet shouldn’t need pruning, as it forms a naturally mounded shape. Before pruning, disinfect your shears by soaking them for five minutes in a solution of 1 part bleach to 3 parts water or 1 part rubbing alcohol to 1 part water and letting them air-dry.

The "Sunshine" privet requires little other care. If kept mulched, it should need watering only during dry periods. You can feed it in early spring – or up to three times during the growing season -- with a 15-5-15 fertilizer at the rate of 1/2 pound per 100 square feet.