Care of Boxwood Plants

Environment

Select a growing environment for boxwood plants with dappled or partial afternoon shade. They will tolerate full morning sun, but afternoon sun and full winter sun may burn the plants and cause foliage to turn orange or brown. For the best results, choose a location with an eastern or northern exposure that is protected from harsh winds. The planting site should also have rich, well-drained soil, as boxwood plants cannot tolerate long periods of standing water. Plant boxwood at the same depth it was grown in the nursery to ensure the shallow roots receive the nutrients they need.

Water boxwood plants thoroughly after planting and continue watering once every 7 to 10 days to keep the soil consistently moist. In very dry climates or during drought-like conditions, increase the frequency of watering to twice per week. Do not water on weeks that receive at least one inch of natural rainfall, as over-watering can lead to fungal problems. Reduce watering to once every two weeks after mid-summer to prepare boxwood plants for winter. Continue watering twice per month until the first frost of winter and then cease. Resume watering in spring after all danger of frost has passed.

Mulch boxwood plants with peat or leaf mold to help conserve moisture and moderate the soil temperature. Apply only a light layer of mulch, no more than one inch thick, over the root zone and do not allow the material to touch the main stem. Excessive mulching can encourage the roots to grow above the soil and under the mulch, which can cause drying or cold damage.

Feed boxwood plants once per year in early spring or late fall. Use a granular fertilizer with an NPK ratio of 10-6-4 at a rate of 1 lb. per 100 square feet for the best results. Spread the fertilizer around the base of the boxwood plant to the drip line, and then water into the soil. Because boxwood has a shallow root system, over-fertilization is a common problem. It can cause yellowing or browning of the leaves and even kill the plant's roots. Make sure to fertilize only when there is adequate soil moisture, or when you can water the soil thoroughly after application.

Cut back dead or dying branches at any time. Do not prune new plants too severely, as this can cause unnecessary stress. Rejuvenate older boxwood plants by cutting them back to about three feet in height. They will look bare for a few years, as they are slow growers. They will, however, begin to look healthy and full in three to four years after a severe pruning. Thin boxwood plants of any age in late winter before new growth begins. Thinning will prevent fungal infections and allow air circulation into the center of the plant.