Maintenance of Boxwood Shrubs

Irrigation and Fertilization

• Proper irrigation is an important aspect of boxwood maintenance, especially for newly planted shrubs not yet fully established. Water boxwoods frequently during the first growth season, keeping the soil consistently moist around the roots. Water slowly and deeply. Avoid light and frequent irrigation. The root zone should always be moistened to a depth of at least 6 to 8 inches. Established boxwoods require at least 1 inch of water per week. Regular fertilization is important as well. Begin with a soil test identifying any nutrient deficiencies. Apply a balanced landscape fertilizer, such as a 10-10-10 blend, at a rate of 1 pound per 100 square feet. Fertilize boxwood in the early spring or late winter. Avoid applying product within 6 inches of the plant stem.

Mulching

• Boxwood shrubs are shallow-rooted and require regular mulch protecting their delicate roots. Hot, dry, exposed soil stunts boxwood growth and makes them susceptible to a number of diseases. Protect the root systems by maintaining a 2 to 3 inch thick layer of organic mulch around the root zone extending outward at least 1 foot beyond the foliage canopy. Avoid black plastic sheeting or landscape fabric. Choose organic mulch materials, such as wood chips, pine needles, straw or bark. Examine mulch levels annually, adding more material as needed maintaining a 2- to 3-inch layer.

Light Pruning

• Boxwood shrubs require regular pruning maintaining healthy growth and an attractive form. Shearing boxwood shrubs regularly maintains their shape, especially for plants trained into topiary or espalier form. Accompany shearing or haircut trimming with internal thinning, allowing increased light and air penetration into the shrub’s interior. Boxwood shrubs produce new growth on newly exposed wood. Thinning stimulates growth on the inner plant stems, leading to fuller, bushier growth. Perform thinning and shearing cuts as needed maintaining the plant’s shape in any season of the year.

Heavy Pruning

• Boxwood shrubs are slow-growing perennials. Removing too much plant tissue in a pruning session adversely affects the plant’s health. Excessively trimmed boxwood shrubs are slow to recover. Drastic reshaping should take place during a period of years, taking care not to remove more than one-third of the tallest branches in the first pruning session. Begin heavy pruning in the early spring, before new growth appears and limit the cuts to outside buds and branches. Remove one-third of the desired foliage the first spring, one-half of the remaining foliage the second and make final pruning cuts in the third consecutive spring. Always prune to maintain a plant shape that is wider than it is tall.