Shrub · Buxaceae
Common Boxwood
Buxus sempervirens
Slow, steady, and evergreen year-round, boxwood is the backbone of a clipped, formal garden.
Full sun
Every 5–10 days
USDA 5–8
5–15 ft · 1.5–4.6 m
Overview
Boxwood is the plant gardeners reach for when they want green structure that holds its shape through every season. It's a slow-growing evergreen shrub from the box family, dense enough to clip into a tight hedge, a low edging, or a rounded ball that anchors a border. Left alone it can climb to 15 feet, but most gardeners keep it far shorter and far neater.
Patience is the price of admission. Boxwood adds only a little growth each year, so a mature hedge represents real time, and you plant it for the long haul rather than a quick screen. The payoff is a shrub that tolerates deep shade to full sun, shrugs off cold down to zone 5, and lives for decades once it's settled in.
The catch is that boxwood comes with a short list of real troubles. Boxwood blight can defoliate a plant in days, leafminers and mites disfigure the leaves, and wet feet invite root rot. Site it well, keep it clean, and give it room for air to move, and most of those problems stay away.
Care
The short version: boxwood takes anything from full sun to full shade, wants evenly moist but well-drained loam, and grows slowly enough that it rarely needs more than a yearly shaping after the last spring frost.
Light
Boxwood is unusually easygoing about light, taking anything from full sun to full shade. It grows densest in sun, but the one thing to avoid is full winter sun on an exposed site, which scorches the evergreen leaves brown.
Water
Keep the soil evenly moist but never soggy, watering roughly every 5 to 10 days once established. The roots sit shallow, so spread 1 to 2 inches of organic mulch to hold moisture and skip cultivating around the base. Overwatering and poor drainage are what invite root rot.
Soil
Plant in well-drained loam that stays evenly moist. Boxwood is relaxed about pH, doing well anywhere from 6.0 to 8.0, so slightly acidic through slightly alkaline ground all suits it. Heavy, waterlogged clay is the soil to fix or avoid.
Temperature
Boxwood is tough across a wide range, hardy from about -20°F to 100°F (-29°C to 38°C). The real risk isn't the thermometer but exposure, since drying winter wind and sun do more damage than cold alone.
Humidity
Ordinary outdoor humidity is all it needs, so there's no level to chase. Air movement counts for far more, because still, damp conditions in a crowded planting are exactly what blight and other fungal diseases want.
Feeding
A balanced fertilizer in spring is enough to keep boxwood vigorous through the year. Pair that yearly feeding with good mulch, and the plant holds its color and density without anything fancier.
Pruning
Shape boxwood after the last spring frost and never before it, or you risk pushing tender growth into a late freeze. Take out dead or diseased branches as soon as you see them, and rake any leaves caught in the branch crotches, since trapped debris is a starting point for disease.
Repotting
Boxwood is rarely repotted and resents being disturbed once it's growing well. In a container, watch for roots circling the pot, water running straight through, or growth that stalls, and move it up a size only when those signs show.
Size & spacing
Plants range from 5 to 15 feet (1.5 to 4.5 m) tall and about as wide, though clipping keeps most far smaller. Give a hedge the room its mature spread demands so air can move freely between plants and disease has a harder time taking hold.
When to plant
Boxwood goes in the ground in spring or early fall, when the soil is workable and the weather is mild. Pick a spot sheltered from harsh wind and full winter sun, and give the roots a season to settle before the extremes of summer or deep cold arrive.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring or early fall, in a site sheltered from strong winds and full winter sun
- Harvest: April to May (greenish-cream, insignificant flowers)
Hardiness
USDA hardiness zones: 5–8
Temperature: down to -29°C
Troubleshooting
Boxwood stays trouble-free for years, then shows its handful of weak spots all at once. Most problems read in the leaves, from sudden browning and defoliation to blisters and stippling, while the worst ones start out of sight at the roots. Match what you see below and act early, since the serious diseases have no cure.
Brown leaf spots, sudden defoliation, and dark stem cankers
This is most likely boxwood blight, a fast-moving fungus that strips a plant of its leaves within days, though Volutella blight can follow winter injury with similar damage. There's no cure once it takes hold. Cut out and bag the diseased stems, rake up every fallen leaf, lay down fresh mulch, and protect what's left with a chlorothalonil fungicide.
Fix:
- Remove and bag diseased stems and rake up all fallen foliage
- Apply fresh mulch over the soil surface
- Apply chlorothalonil, or chlorothalonil mixed with thiophanate methyl, fungicide
Yellowing foliage with rotted roots and peeling crown bark
When the whole plant fades from green to yellow and the roots come up dark and mushy, the cause is Phytophthora root rot sitting in wet, poorly drained soil. Check the crown, where the bark peels away once it's infected. There's no spraying your way out of this one, so fix the drainage, amend heavy clay, or move the plant to a raised bed and ease off the water.
Fix:
- Improve soil drainage
- Amend heavy clay soils or plant in raised beds
- Avoid overwatering
Blistered, swollen leaves with yellow blotches
Those raised blisters are the work of the boxwood leafminer, whose larvae feed inside the leaf. Split a blistered leaf open and you'll find the orange maggots in the mine. Watch for the adult flies from mid-April into early May, then treat with a foliar spray of acephate or spinosad, or a soil drench of imidacloprid.
Fix:
- Apply acephate or spinosad foliar spray to larvae in mines
- Use malathion contact spray against adults
- Apply soil-applied dinotefuran or imidacloprid
Dingy, silvery-stippled leaves
Fine yellow scratches and a dull silvery cast point to the boxwood mite. Tap a branch over a sheet of white paper and watch for the tiny mites crawling across it. Knock them back with horticultural oil at 1 to 2 percent or insecticidal soap, and keep stressed plants out of hot, baking sun where mites multiply fastest.
Fix:
- Apply horticultural oil at 1-2 percent to kill eggs and adults
- Apply insecticidal soap
- Apply tau-fluvalinate miticide if needed
Cupped new leaves with white waxy fluff
The boxwood psyllid sucks sap from the new growth and leaves it curled and cupped. Pry open the distorted shoots and you'll see small pale-green nymphs under a white waxy coating. The damage is mostly cosmetic, so leave light cases alone and only spray acephate when an infestation gets heavy.
Fix:
- Treat only heavy infestations
- Apply acephate foliar spray
- Apply soil-applied dinotefuran or imidacloprid
Brownish-yellow foliage in late winter
Boxwood that sits in open winter sun and drying wind often takes on a dull brownish-yellow cast called winter bronzing. It looks alarming but rarely harms the plant, and the fresh spring growth usually comes in a healthy green. Site or move plants where they're sheltered from wind and harsh winter sun, water well in fall, and mulch over the shallow roots.
Fix:
- Site or transplant plants where they are sheltered from winter wind and full winter sun
- Ensure adequate fall soil moisture before winter
- Apply organic mulch to protect shallow roots
Toxicity
Boxwood is toxic, and no part of it is safe to eat. The leaves and stems carry steroidal alkaloids, chiefly buxine, that bring on vomiting and diarrhea in pets and people alike, and large amounts can lead to seizures or respiratory failure in horses and livestock. The bitter taste stops most animals before they swallow much, but keep pets, grazing stock, and children away from the foliage and any prunings.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Moderate
A cat that chews the leaves usually drools and then vomits, with diarrhea close behind. The bitter taste tends to stop most cats before they eat enough to do real harm.
Dogs Moderate
Expect vomiting and diarrhea soon after a dog nibbles the foliage or chews on fallen prunings. Keep clippings raked up and out of reach during a trim.
Horses Severe
Horses are hit hardest. The alkaloids can bring on colic, diarrhea, seizures, and in large amounts respiratory failure, so keep boxwood and its trimmings well away from any paddock.
Rabbits Toxic
The same buxine that sickens other animals makes boxwood unsafe for rabbits. Never offer the leaves or stems, and fence the shrubs off from any free-ranging bunny.
Livestock Severe
Cattle, goats, and sheep can suffer serious digestive and respiratory trouble from the foliage, and heavy grazing has proven fatal. Bitter leaves deter most stock, but hungry animals will still try them.
Birds Toxic
No part of boxwood is safe for birds to eat. Keep poultry and pet birds from pecking at the leaves or scattered clippings.
People Caution
No part of boxwood is edible, and eating the leaves or stems can cause vomiting and diarrhea. The sap also irritates sensitive skin, so wear gloves when you prune and keep curious children away.
Sap can cause contact dermatitis in sensitive people; wear gloves when pruning.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Boxwood comes in everything from low spreading mounds to narrow upright columns, and a few cultivars are worth knowing by name for their shape or their resistance to pests.
Vardar Valley
A low, spreading form that tops out around 2 to 3 feet with bluish leaves, and it shrugs off the boxwood leafminer that troubles other types.
Suffruticosa
The classic English boxwood is a dense, fragrant dwarf that grows painfully slowly and happens to be the least able to fend off leafminers.
Dee Runk
A narrow column that climbs to about 8 feet tall while staying just 2.5 feet wide, which makes it a natural for a tight vertical accent.
Elegantissima
A variegated cultivar prized for the creamy-white edges that ring every leaf.
How to propagate
Boxwood is patient but reliable to multiply, and taking cuttings is the surest way to get a true copy of a plant you already like.
Stem cuttingsModerate
Mid-July to early fall (semi-hardwood, current season's growth) · Several weeks to a few months to root
Boxwood grows readily from cuttings if you give it time. Take semi-hardwood pieces of the current season's growth from mid-July into early fall, choosing only healthy, disease-free plants, and keep the cuttings moist and shaded while you work. Rooting is unhurried and runs anywhere from several weeks to a few months, and hardwood cuttings strike just as well.
Myths
Boxwood is harmless to pets because it is just a common landscape hedge.
Every part of the plant holds alkaloids that are toxic to dogs, cats, and horses. A pet that chews the foliage gets vomiting and diarrhea, and horses can react far worse. Being a familiar hedge doesn't make it safe to eat.
A spray will cure boxwood blight once a plant is infected.
Nothing cures the disease once it's in the plant. Boxwood blight can only be managed, never reversed, by cutting out infected material, keeping the area clean, and using protective fungicides to slow it from spreading to healthy plants.