Shrub · Cupressaceae

Creeping Juniper

Juniperus horizontalis

Give it full sun and soil that drains, and this tough evergreen mat looks after itself.

Light

Full sun

Water

Every 10–⁠21 days

Hardiness

USDA 3–⁠9

Mature size

6–⁠18 in · 15–⁠46 cm

Pet-safe
Creeping Juniper

Overview

Creeping juniper grows low and wide, an evergreen that mats across the ground and stays right down at boot height. Part of the cypress family, it ranges through the cold stretches of North America in the wild, which explains how it laughs off winters as deep as -40°F (-40°C). One plant can sprawl 4 to 8 feet (122 to 244 cm) wide yet reach hardly a foot in height.

Plant it as a ground cover and watch it earn its keep on slopes, in rock gardens, and along hot, dry banks that defeat almost everything else. Once settled, it asks next to nothing, taking poor sandy soil, salt, drought, and fierce sun in stride. Its trailing branches root the moment they meet the ground, so the mat weaves itself tighter season after season.

Wet feet remain the single deal-breaker. Set it where water drains in a hurry, keep the foliage dry, and grant it space and airflow, and it stays healthy and trouble-free for decades. Pack it in tight or leave it sitting in soggy ground, though, and that toughness gives way to blight and root rot.

Care

The short version: full sun, soil that drains fast, and barely a drink once it has rooted in. Pass on the rich beds and the regular watering, hand each plant space to sprawl, and let it parch a little before you water again.

Light

Pour on the full sun, as much as you can spare. Bright light packs the mat tight and holds the color crisp, while shade thins the foliage out and rolls out the welcome mat for blight, which loves damp, packed-in growth.

Water

After it roots in, the plant turns very drought tolerant and asks for water only every 10 to 21 days, if even that. Soak it deeply but seldom, let the soil parch between drinks, and steer the spray clear of the foliage, since soggy leaves usher in tip blight.

Soil

Above everything, hand it fast-draining soil, be it sandy, rocky, or downright poor. It rolls with a broad pH band from 5.5 to 8.0 and settles happily into lean ground, yet it will perish in anything that holds water.

Temperature

Here stands one rugged evergreen, hardy clear across -40°F to 100°F (-40°C to 38°C). Savage winters and scorching summer heat barely register, which is exactly why it thrives on bare banks where gentler plants give out.

Humidity

Creeping juniper goes for low humidity and dry air right around its foliage. Damp, motionless air works against it, so never add moisture; instead, open the plant up and let air slip freely through it.

Feeding

Feeding hardly enters the picture. A light balanced or slow-release fertilizer come spring earns its place only when growth has stalled, and a plant set in average soil cruises along for years on absolutely nothing.

Pruning

Pick a stretch of dry weather to cut away dead, diseased, or blight-killed tips, dropping several inches past the damage into healthy wood and wiping your blades clean between cuts. Thin the mat from time to time to crack it open and keep air moving through the middle.

Repotting

Repotting comes up rarely, and most plants spend their whole lives rooted in the ground. In a pot, keep an eye out for roots circling or shoving through the drainage holes, water sliding straight through, or growth that flat-out halts.

Size & spacing

Plants hug the ground at 6 to 18 inches (15 to 46 cm) tall yet fan out 4 to 8 feet (122 to 244 cm) across. Space them generously so they knit together over time without crowding, which keeps air circulating and disease at bay.

When to plant

Set creeping juniper out in spring or early fall, while the soil works easily and the roots can dig in ahead of fierce heat or a hard freeze. Small cones form in late spring, and the blue berry-like cones need two full seasons to ripen. Since nothing here gets harvested, your timing simply hands the roots a running start.

Northern hemisphere

Plant Mar–May
Bloom May–Jun
Plant Sep–Oct

Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.

  • Plant: Spring or early fall
  • Harvest: Inconspicuous cones in late spring; blue berry-like cones mature over two seasons

Hardiness

USDA hardiness zones: 3–9

Temperature: down to -40°C

Troubleshooting

Nearly every juniper headache springs from one of two roots: foliage left wet and soil that refuses to drain. Watch the tips, the inner branches, and the roots for the first hints, and you can jump in before one bad patch races outward. Find your match below, then move while there is still time to turn it around.

Severe

Whole plant thinning while the roots go brown

Soggy ground triggers Phytophthora root rot, turning healthy white roots a reddish-brown and cutting off the food supply to everything above. No spray will rescue roots that have already gone. Let the ground dry, dig out any plant that has crashed hard, and move it to a spot that sheds water fast.

Fix:

  • Allow soil to dry out; mildly affected plants may recover
  • Improve drainage by amending with organic matter or pine bark or planting in raised beds
  • Remove and discard severely affected plants
  • Replant with resistant species in well-drained sites
Setback

Branch tips fading and dying back from the ends

Reach for the pruners: this is tip blight, the work of two fungi that pounce when foliage sits wet. Fresh spring and summer shoots draw in Phomopsis, while Kabatina targets older, wounded tips come late winter. Wait for a dry spell, then snip the dead ends out several inches down into living wood, sterilizing the blades after each and every cut.

Fix:

  • Prune out blighted tips in dry weather, cutting several inches into healthy wood
  • Disinfect pruners between cuts with 10 percent bleach or 70 percent alcohol
  • Discard or destroy infected prunings
  • Apply a labeled fungicide preventively for Phomopsis as new growth emerges if pressure is high (no effective fungicide for Kabatina)
Setback

Flat, speckled foliage laced with fine webbing

Specks and webbing give away spider mites, which explode in numbers on hot, dusty, stressed plants. Their peak mischief comes in the cooler runs of spring and fall. Knock them loose with a forceful jet of water first, and turn to insecticidal soap or oil only if the pests rally and return.

Fix:

  • Dislodge mites with a strong, regular spray of water
  • Apply insecticidal soap, horticultural oil, or a miticide if needed
  • Avoid broad-spectrum insecticides that kill mite predators
Setback

Spindle-shaped bags swinging from chewed branches

Those swaying bags belong to bagworms, caterpillars that munch from inside a silk pouch sewn together with scraps of your juniper. Every bag is packed with eggs that ride out winter and hatch into the next generation. Strip the bags off through winter and early spring, then hit young larvae with Bt should they show.

Fix:

  • Handpick and destroy bags in winter and early spring to remove overwintering eggs
  • Spray Bt or another labeled insecticide on young larvae in spring
Setback

Tiny white scales and a sticky film on the needles

Little white or gray bumps clinging under the needles are juniper scale, sap-suckers that leave foliage discolored and tacky with honeydew. A dormant oil spray come late winter smothers them before they wake. Then catch the crawlers in spring, and an insecticide closes out the job.

Fix:

  • Apply horticultural oil as a dormant spray in late winter
  • Treat crawlers with a labeled insecticide during the spring growth flush
Cosmetic

Brown galls pushing out orange jelly horns in spring

Those galls signal cedar-apple rust, a fungus that can only finish its life cycle with an apple or crabapple growing close by. The firm brown knots balloon into glowing orange tendrils through wet spring weather. Cut the galls away, and from the start, plant junipers well clear of any apples and crabapples.

Fix:

  • Prune out and destroy galls
  • Apply a labeled fungicide (mancozeb or propiconazole) if needed
  • Avoid planting near susceptible apples or crabapples
Cosmetic

Dead brown branches hiding inside the mat

As the canopy thickens, light and air stop reaching the shaded core, so the inner branches quietly die back while the outer growth keeps its color. Blame siting and density here, not a pathogen. Thin the plant to let it breathe, pull the dead wood during dry weather, and set it in full sun with elbow room.

Fix:

  • Thin and prune to open up the canopy and improve air movement
  • Remove dead interior branches in dry weather
  • Site in full sun with adequate spacing

Toxicity

Keep creeping juniper around the house and garden with full confidence. It stays off the ASPCA toxic-plant lists, and the worst it tends to do is leave a pet with a mild stomach upset after eating plenty of the aromatic berries or foliage. The real annoyance is that prickly foliage, which can scratch tender skin, so glove up before you prune.

Safe for

People · Cats · Dogs · Horses · Rabbits · Livestock · Birds

Cats Caution

Fine company for a cat, by and large. Chew through enough of the scented foliage or berries, though, and the volatile oils can leave the stomach a little queasy, so it pays to nudge your cat away from the plant.

Dogs Caution

A nosy sniff poses no threat at all. Down a pile of berries or foliage and a dog might drool, vomit briefly, or pass loose stool, all of which sorts itself out without help.

Horses Caution

Nibbling the stray sprig causes no bother, yet the berries and resinous oils can upset a horse's digestion in bulk, so keep them from grazing it hard.

Rabbits Safe

Poses no recognized risk to rabbits, and the thick, prickly foliage holds so little appeal that they generally walk on past.

Livestock Safe

Cattle, goats, and sheep graze the same pasture safely, because that resinous, sharp foliage seldom draws them in to eat much of it.

Birds Safe

Great news for birds, which feast on the blue cones and carry the seed far and wide.

People Safe

Planting and handling it is safe, and certain juniper berries flavor food as a culinary spice. That prickly foliage can scratch or bother tender skin, so pull on gloves before you prune.

Aromatic foliage and berry-like cones may cause mild stomach upset if eaten in quantity; the prickly foliage can also irritate skin in sensitive people.

Varieties

Nearly every creeping juniper on offer is a named cultivar picked for its foliage color and just how flat it lies. Here are the ones you will bump into time and again.

Wiltonii (Blue Rug)

Expect a tight, ground-skimming carpet of silvery blue-green foliage that stays remarkably flat.

Bar Harbor

Quick to spread and low to the ground, with feathery blue-green foliage that warms to a mauve or purplish cast through winter.

Plumosa (Andorra)

Soft gray-green foliage mounds up and shifts to a clear plum-purple as cold weather arrives.

Mother Lode

A Wiltonii seedling that swaps in golden-yellow foliage atop the same flat, very low carpet.

Lime Glow

Lively lime to golden foliage builds a low vase-shaped mound that bronzes up over winter.

How to propagate

Three routes let you grow more creeping juniper, and which one suits you comes down to how patient you feel and whether the new plants must match their parent.

Stem cuttingsModerate

Late fall to winter using semi-hardwood cuttings · Several weeks to a few months to root

Want a named cultivar to come back exactly true to type? Cuttings deliver. Pull semi-hardwood cuttings from late fall into winter, dust them with rooting hormone, and stay patient, because juniper roots slowly and can take several weeks to a few months to take hold.

LayeringEasy

Spring through summer · One or more seasons

Layering taps right into how this plant already behaves, since its trailing branches root themselves wherever they settle on the soil. Pin a low branch down from spring through summer and allow it a season or more to anchor before you sever it.

SeedDemanding

After cold stratification · Slow and variable, often a year or more

Seed rewards only the truly patient grower. Give it cold stratification up front, then brace for slow, patchy germination spread over a year or more, and know it will not bring a cultivar back true to type.

Myths

Myth

Creeping juniper is poisonous and will seriously harm any cat or dog that touches or nibbles it.

Reality

ASPCA toxic-plant lists make no mention of Juniperus, and gardeners treat the plant as non-toxic. At worst, eating a lot of the aromatic foliage or berries causes a mild, self-limiting stomach upset rather than anything dangerous.

Myth

Junipers thrive in moist, rich soil and do better with frequent watering.

Reality

Drought is this plant's element, and it craves ground that sheds water quickly. Wet, heavy, or overwatered ground is what brings on Phytophthora root rot, far and away the likeliest killer.

Sources