Shrub · Cupressaceae

Creeping Juniper

Juniperus horizontalis

Site it in full sun with sharp drainage, and this rugged evergreen mat needs little from you.

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 is a prostrate, mat-forming evergreen that runs wide while hugging the ground. As a member of the cypress family native to the cold zones of North America, it carries the cold hardiness to endure winters reaching -40°F (-40°C). One plant can extend 4 to 8 feet (122 to 244 cm) sideways yet rise only about a foot.

It earns its place as a ground cover on slopes, through rock gardens, and across hot, dry banks where few plants persist. Demands are minimal once it is rooted in, since it copes with lean sandy ground, salt, drought, and intense sun. Because the trailing branches root at the points where they meet the soil, the colony stitches itself into a continuous mat over the years.

Its single intolerance is poor drainage at the roots. Set it where soil drains quickly, keep moisture off the needles, and allow air and space around it, and it remains healthy and trouble-free for decades. Pack it tight or leave it in standing wet, and that durability gives way to blight and root rot.

Care

The short version: full sun, soil that drains fast, and minimal water after establishment. Avoid rich beds and frequent irrigation, allow each plant room to run, and let the root zone dry between waterings.

Light

Creeping juniper demands full sun in generous supply. Strong light keeps the mat tight and the color accurate, while shade opens the foliage up and creates the damp, crowded conditions blight exploits.

Water

After establishment it is very drought tolerant, asking for water at most every 10 to 21 days. Irrigate deeply but seldom, let the root zone dry in the gap, and keep the spray off the needles, because wet foliage is what tip blight needs to take hold.

Soil

Above everything, supply fast-draining soil, be it sandy, rocky, or poor. It accepts a broad pH span of 5.5 to 8.0 and tolerates lean ground, but ground that stays saturated will finish it off.

Temperature

Few evergreens are this durable, with a working range of -40°F to 100°F (-40°C to 38°C). It withstands savage winters and scorching summers alike, which is precisely why it holds exposed banks where less hardy plants give out.

Humidity

Creeping juniper favors low humidity and dry air at the foliage. Moist, stagnant air works against it, so the remedy is never to raise moisture but to open the canopy so air circulates through it.

Feeding

Feeding is hardly required. A light balanced or slow-release fertilizer in spring is useful only where growth has stalled, and a plant in average soil can run for years on nothing.

Pruning

Prune in dry weather to take out dead, diseased, or blight-killed tips, going several inches below the damage into sound wood and sterilizing the blades between cuts. Thin the mat periodically to open it and keep air moving through the center.

Repotting

Repotting is seldom needed, and most plants spend their entire lives in the ground. In a container, look for roots circling or pushing out the drainage holes, water passing straight through, or growth that has simply halted.

Size & spacing

Plants hold low at 6 to 18 inches (15 to 46 cm) tall yet reach 4 to 8 feet (122 to 244 cm) across. Place them far enough apart to close the gaps over time without crowding, which sustains airflow and suppresses disease.

When to plant

Set creeping juniper out in spring or early fall, while the soil works easily and roots can establish ahead of peak heat or hard freezes. Small cones appear in late spring, and the blue berry-like cones need two full seasons to ripen. Since there is nothing to harvest, the whole point of timing is letting the roots get a head 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 problem comes down to a pair of causes: needles that stay wet and soil that holds water. Watch the early cues at the tips, in the inner canopy, and at the roots, and intervention can stop a small patch before it widens. Find the match below, then respond while a response still counts.

Severe

General decline with roots discolored reddish-brown

Saturated soil triggers Phytophthora root rot, which turns healthy white roots reddish-brown and cuts off the water and nutrients the canopy depends on. No foliar treatment will rebuild roots that have already rotted. Withhold water so the soil dries, dig out anything severely declined, and reset it where drainage is reliable.

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

Foliage tips discoloring and dying back progressively

What you are seeing is tip blight, the work of two fungi that establish when foliage cannot dry. Phomopsis targets the soft flush of spring and summer, whereas Kabatina colonizes older, injured tips and shows its damage in late winter. Cut the dead tips away during dry conditions, several inches down into living wood, sterilizing the blades after each pass.

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

Stippled, off-color foliage showing fine webbing

Yellow stippling paired with webbing is the calling card of spider mites, which multiply quickly on plants that are hot, dusty, and under stress. Their populations peak in the cooler windows of spring and fall. Knock them back with a forceful jet of water first, turning to insecticidal soap or oil only when they 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 silk cases suspended from defoliated branches

The hanging cases are bagworms, caterpillars that feed while sheltered inside a silk bag they camouflage with shreds of juniper foliage. Each case is packed with eggs that overwinter and seed the following season's infestation. Strip the bags by hand across winter and early spring, then treat any emerging larvae with Bt.

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

Minute white scales with honeydew on needle undersides

The white or gray specks under the needles are juniper scale, sap-feeding insects that drain color from the foliage and coat it in sticky honeydew. A dormant oil applied in late winter coats and smothers them before they become active. Target the spring crawlers next, and an insecticide closes out the season.

Fix:

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

Woody galls extruding orange gelatinous horns in spring

Those swellings are cedar-apple rust, a Gymnosporangium fungus that cannot finish its cycle without an apple or crabapple host close by. The woody brown lumps push out vivid orange tendrils during damp spring spells. Cut the galls off, and from the start position junipers well clear of any apple or crabapple.

Fix:

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

Interior branch dieback within the dense mat

As the canopy thickens, the interior is cut off from light and air movement, so the inner branches die back even while the outer surface stays green. This is a density and siting issue, not pathogen damage. Thin the plant to let light and air reach the center, clear the dead wood in dry weather, and grow it in full sun with space around it.

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

Creeping juniper is safe to grow around the home and garden. It does not appear on the ASPCA toxic-plant lists, and the usual worst case is a mild stomach upset when a pet eats a good deal of the aromatic berries or foliage. The greater annoyance is the prickly foliage, which can scratch sensitive skin, so put on gloves before pruning.

Safe for

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

Cats Caution

Mostly harmless to share space with. The volatile oils in the aromatic foliage and berries can give a cat a mildly upset stomach if it chews a good deal, so discourage repeated browsing.

Dogs Caution

A passing sniff poses no threat. Consuming a fair amount of foliage or berries may trigger some drooling or a short episode of vomiting and loose stool that resolves without treatment.

Horses Caution

An occasional nibbled sprig is harmless, yet the resinous oils and berries can upset a horse's digestion in larger amounts, so keep heavy browsing in check.

Rabbits Safe

No recognized risk to rabbits, and the thick, prickly growth offers little to attract them, so they generally pass it by.

Livestock Safe

Cattle, goats, and sheep graze nearby without issue, because the sharp, resinous foliage seldom draws them in to eat much of it.

Birds Safe

Entirely suitable for birds, which feed on the blue cones and disperse the seed in the process.

People Safe

Safe to grow and handle, and certain juniper berries serve as a culinary spice. Because the prickly foliage can scratch or irritate sensitive skin, glove up before pruning.

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 all creeping junipers in the trade are named cultivars selected for foliage color and how low they keep. These are the ones most likely to cross your path.

Wiltonii (Blue Rug)

Its silvery blue-green foliage presses into an exceptionally flat mat right against the ground.

Bar Harbor

A low, quick-spreading selection whose feathery blue-green growth shifts toward mauve to purplish through winter.

Plumosa (Andorra)

Soft gray-green foliage on a mounded form deepens to a clear plum-purple as the cold arrives.

Mother Lode

A Wiltonii seedling that holds golden-yellow foliage on the same very low, flat mat.

Lime Glow

A low vase-shaped mound of bright lime to golden foliage that shifts to bronze tones in winter.

How to propagate

Three methods will increase your creeping juniper stock, and the right choice hinges on how patient you are and whether the new plants must be identical to the parent.

Stem cuttingsModerate

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

Cuttings are how you preserve a named cultivar's exact traits. Collect semi-hardwood cuttings across late fall into winter and dip them in rooting hormone, because juniper roots reluctantly and may need several weeks to a few months to establish.

LayeringEasy

Spring through summer · One or more seasons

Layering works with the plant's own habit, since trailing branches naturally strike roots wherever they contact the soil. Anchor a low stem to the ground from spring through summer and allow a season or more for rooting before severing it.

SeedDemanding

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

Seed is the demanding route reserved for the patient. It requires cold stratification up front, then sprouts slowly and erratically across a year or more, and the offspring will not match a cultivar.

Myths

Myth

Even a light touch or nibble of creeping juniper will badly poison a dog or cat.

Reality

Juniperus is absent from ASPCA toxic-plant lists and is generally handled as non-toxic. The most that heavy nibbling of the aromatic foliage or berries produces is a mild, self-resolving stomach upset rather than genuine harm.

Myth

Junipers perform best in rich, damp soil and reward regular irrigation.

Reality

This is a drought-adapted plant that demands free-draining soil. Saturated, heavy, or overwatered ground is exactly what sets off Phytophthora root rot, the single most lethal problem it faces.

Sources