How to Grow Beautiful Boxwood Shrubs

Growing Zones:

5 to 9 for most, with a few varieties hardy to Zone 4.

How big do boxwoods get?

Varieties range from 1 to 20 feet tall, 2 to 8 feet wide.

Do boxwoods like sun or shade?

They prefer partial or dappled shade, but can tolerate full sun — short of scorching mid-day sun. Overexposure to sun causes burning and bronzing of foliage. If planting in a brighter location, look for varieties that may be more tolerant of sun, such as ‘Morris Midget’.

Do boxwoods bloom?

Small, insignificant, yellow-green flowers bloom in spring.

Color and characteristics:

Mainly grown for their foliage; their leaves grow opposite, are lance-shaped to almost rounded, and are leathery to the touch. Many have darker blue-green foliage, others are a paler green color, and some have variegated leaves.

Are boxwoods toxic?

Boxwood bushes contain an alkaloid that is toxic to dogs, cats and horses, as well as humans. Contact with the sap can cause skin irritation. (See more Common Poisonous Plants for Dogs and Cats.)

Soil:

Boxwood bushes are extremely flexible and can adapt to various types of well-drained soils. Ideal soil pH is 6.5 to 7. For more on proper soil preparation and how to adjust your pH if needed, read Garden Soil 101.

Amendments & fertilizer:

Apply a balanced all-purpose fertilizer in spring to promote foliage growth, and again in fall to encourage root growth. Apply the fertilizer throughout the root zone, which extends beyond the crown of the plant. Be careful; their shallow root systems can be damaged by over fertilizing.

Watering:

Water newly planted shrubs regularly for the first year, especially during hot, dry weather. In their second year, root systems are still developing, so continue to water regularly if rainfall isn’t enough. Once established, they’re quite drought tolerant and only need extra watering during dry spells. Water at the base of the plant to keep the foliage dry and conserve moisture with a layer of mulch that extends 12 to 15 inches past the foliage line.

Winter care:

Provide extra protection from cold temperatures and winds with burlap wraps, decorative protection, or a windbreak. Apply a good layer of mulch to keep the roots insulated; this will also conserve moisture to prevent dehydration damage from cold winter winds.

If bronzing of the foliage does occur, resist the temptation to cut it back immediately. The new growth that is prompted from cutting won’t be any hardier than what was damaged, so hold off until spring when new growth can make a comeback.

Diseases and pests:

Boxwood leaf miners, scale insects, lesion nematodes, caterpillars and mites can be a problem; treat with organic neem oil or insecticidal spray. They can also be susceptible to powdery mildew, Pythium root rot, canker and leaf spots. Boxwood blight is a serious problem in many states. See below for more information and planting alternatives.

Deer resistance:

A useful part of a deer-resistant garden, as the same alkaloid that makes them toxic also makes them distasteful and can give off a pungent scent, deterring deer.

When to prune boxwood:

Trimming or shearing encourages new growth and is best done in late spring or summer. Avoid pruning or trimming in fall or winter, because the new growth can be damaged by frost.

How to prune boxwood:

When trimming boxwood, don’t overdo it. While a nice, compact bush may look healthy on the outside, that dense outer foliage (caused from over pruning) can keep air and light from getting to the inner part of the plant. Thin the outer growth annually so that air and light can get in, and prune away any dead or diseased branches from the center of the plant. Shearing can be done with hand pruners, hedge clippers or electric trimmers.