Common privet bonsai

Placement

Ligustrum vulgare is an outdoor bonsai. Native to much of Europe, it is fully hardy and needs no greenhouse. Give it a bright spot that gets direct sun for at least part of the day. It also tolerates fairly deep shade, which leaves plenty of freedom in choosing where it sits.

Winter mainly decides how the foliage behaves. Being semi-evergreen, privet keeps its leaves when the season is mild and drops them when it is harsh; this leaf drop leaves no lasting damage, and the new spring shoots clothe the tree again. Keep it outdoors through fall so it hardens off gradually. Extra protection is only needed once temperatures fall below 14 °F: at that point the root ball, which is more exposed in a pot than in the ground, must be sheltered from frost. Do not bring a tree that has spent the fall outdoors into a heated room.

Soil mix

Privet is not fussy: a standard bonsai mix suits it. A common mix for deciduous trees is half akadama, a quarter pumice and a quarter lava rock. Akadama holds water, while pumice and lava rock provide drainage and air. Sift the akadama to remove dust, which clogs the pot. In a rainy climate, increase the share of lava rock; if you cannot check the tree often, increase the akadama. Because akadama breaks down over the years, renewing the mix at each repotting keeps the root ball airy.

Watering

Do not follow a calendar: observe. Water thoroughly as soon as the surface of the mix starts to dry, until water runs out of the drainage holes. In hot weather, the root ball of a privet in full leaf dries quickly, so check it often. In winter the leafless tree drinks little: water less often, but never let the root ball dry out completely, even during frosts. Very hard water used all the time can cause chlorosis, a yellowing of the leaves from nutrient deficiency.

During the growing season, give a solid organic fertilizer every four weeks, or a liquid fertilizer every week on soil that is already moist. Some growers prefer to feed every two weeks throughout the season. Stop feeding when growth stops and right after repotting.

Pruning

Privet takes pruning extremely well, even into old wood, from which it readily regrows. Hard pruning, to reduce a trunk or remove a thick branch, is done at the end of winter or the very start of spring, before growth begins. For the rest of the year, trim throughout the growing season to keep the shape. Remove oversized leaves and shoots with overly long internodes, which make the outline look heavy. If you want to see the fragrant white panicles of early summer, do not shorten the shoots before they bloom.

Defoliation reduces leaf size and increases branching. Do it in early summer, once the spring growth has hardened off, cutting the leaf blade and leaving the leaf stalk in place. Keep it for healthy, vigorous trees, and never in the same year as repotting or hard pruning. Partial defoliation of the top alone shifts vigor toward the lower branches; afterward, keep the tree in partial shade for about a month.

Old privet hedges, clipped for years, make excellent starting material, with thick, gnarled trunks. Avoid variegated forms, however, which are less suited to bonsai.

Wiring

Wiring can be done in any season, but spring and summer are the best times. The bark on the twigs is soft and marks easily: use aluminum wire about a third as thick as the branch, wound at roughly 45° and anchored with one or two turns around the trunk. During the growing season branches thicken quickly and the wire can bite in within a few months, so check it often and remove it by cutting it at every turn rather than unwinding it. To bend a thick branch, first protect it with damp raffia, or use a guy wire anchored to a strong root or to the pot.

Repotting

Repot in spring, when the buds begin to extend. A young tree in training can be repotted every year; a more mature tree every two to three years, once the roots circle the root ball. Privet tolerates root pruning well, but do not remove more than a third of the root mass. Tie the tree into the pot with wire, work the mix in with a chopstick to remove air pockets, and water thoroughly. Afterward, avoid scorching sun, fertilizer and hard pruning until the tree recovers.

This privet suits the informal upright style, with one or several trunks, and every tree size. It propagates easily from semi-ripe cuttings in summer, hardwood cuttings in winter and air layers in late spring; seed is possible but slow. Watch for aphids, scale insects, whiteflies, thrips, weevils and leaf miners, as well as leaf spots, powdery mildew and wilt. Every part of the plant is toxic, especially the berries: the common privet plant profile covers these risks in detail.