How to Plant & Care for Japanese Boxwoods

Japanese boxwood (Buxus microphylla var. japonica) works well in hedges or foundation plantings. Growing a successful shrub begins at planting. Once established, Japanese boxwood needs some ongoing care, but is not a high-maintenance plant. This evergreen shrub grows 6 to 8 feet wide and 10 to 15 feet tall with a compact growth habit. Japanese boxwood grows in U.S. Department of Agriculture plant hardiness zones 6 through 9.

Plant Japanese boxwood 3 feet apart in a row to create a hedge. For a more informal planting stagger boxwood shrubs leaving at least 3 feet between them. Fall and spring are the best times to plant new shrubs. In mild climates where winter frosts are light, you can plant at any point through the winter. Pick a spot out of the wind in full sun to part shade. You can grow boxwood in full shade, but growth will be slowed by the lower light. Japanese boxwood grows best in loamy soil that drains well.

Gloves

Shovel

Put on gardening gloves to protect your hands during digging and planting.

Dig the hole the same depth as the boxwood's root ball.

Remove the root ball of the Japanese boxwood from the nursery pot and set it in the hole. Handle the shrub by the base of the trunk and the root ball to minimize stress and damage.

Take a look at the top of the root ball, it should be level with the surface of the soil. If necessary, dig the hole a little deeper, or add soil under the root ball until it sits level with the rest of the garden.

Push the soil in around the roots, filling in any holes and air pockets as you work. Bring the soil level up to the base of the trunk.

Use the same soil to fill the hole that you dug out to make the hole. Adding organic matter or other amendments to the soil can cause drainage problems. You don't need to amend the planting area before planting boxwood shrubs.

Water Japanese boxwood right after planting so the soil is damp 12 inches deep. Use a soaker hose so the water enters the soil slowly and has a chance to seep down to the roots. Aim to dampen the soil from the base of the trunk out past the outer branch tips. For the first two years, water weekly during dry weather, especially in summer. Water enough each time to dampen the soil 12 inches deep. Once established, you can extend watering to 10-day intervals during dry weather.

Mulch the area under boxwoods with a 1- to 2-inch-deep layer of compost, bark, pine straw or other organic mulch material. Spread the mulch starting 1 to 2 inches from the base of the trunk out to 12 inches past the outer leaves. The mulch should not touch the plant's trunk.

Fertilize Japanese boxwood early in spring, just before you see new green growth. Use a balanced 10-10-10 fertilizer. Measure out 1 1/2 cup of fertilizer for a 10 by 10 foot area, or 100 square feet. Sprinkle the fertilizer on the soil evenly starting 6 inches from the base of the trunk and extending out to the area under the outer branch tips. Water the area well after spreading the fertilizer.

Trim or shear Japanese boxwood in the spring after the last expected frost date in your area. Use a pair of hedge clippers to prune boxwood into a formal hedge or rounded shape.

After clipping Japanese boxwood, clean your hedge clippers in a mixture of equal parts rubbing alcohol and water to sanitize the blades. Allow the blades to soak for five minutes, then rinse them with water.

Japanese boxwood is one of the more pest-resistant members of this shrub group, but that doesn't make it immune to problems. Two pests to look out for are boxwood leafminer and boxwood mites.

Boxwood leafminer larvae feed inside the leaf. You will see blistering, raised areas and brown splotches on the affected leaves. In summer, keep an eye out for swarms of pale red flylike insects around boxwood. These are the adults and they will lay eggs in the leaves.

Prune off any affected branches and destroy them as soon as you see signs of larvae, generally in spring. This will keep the population from spreading. One of the best ways to keep this damaging pest in check is by encouraging predatory insects, such as garden spiders.

Boxwood mites are tiny sap-sucking insects that feed on the underside of leaves. You will see microscopic, tan insects -- get out your magnifying glass -- generally on the underside of the leaves. The affected leaves show brown flecks or marks on the surface.

Spray boxwood mites with a diluted insecticidal soap making sure to thoroughly saturate the affected parts of the leaf. Insecticidal soaps work on contact so it's important to get good coverage. Mix 4 teaspoons of the concentrated soap with 1 quart of water in a spray bottle, shake it up and spray the mites directly.

Insecticidal soaps are less toxic than some chemical pesticides, but practice safety when using and handling. Wear gloves, long sleeves and eye protection. Spray on a windless day, ideally early in the morning or late in the evening. Avoid spraying beneficial insects like bees, garden spiders and other pollinators. Keep mixed and concentrated insecticidal soaps out of reach of children.