Shrub · Cupressaceae

Creeping Juniper

Juniperus horizontalis

Set it somewhere sunny with soil that drains fast, and this hardy evergreen carpet mostly fends for 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 is a low evergreen that mats out wide and keeps its head down near the soil. It's a member of the cypress family and grows wild across the cold stretches of North America, which explains how it laughs off winters as low as -40°F (-40°C). One plant can sprawl 4 to 8 feet (122 to 244 cm) sideways while barely topping a foot in height.

So why do gardeners love it? It's the go-to ground cover for slopes, rock gardens, and hot, dry banks where hardly anything else clings on. Once it's rooted in, it asks for next to nothing and just rolls with poor sandy soil, salt, drought, and full-on sun. Those trailing branches root wherever they land, so the mat stitches itself together as the years go by.

The one thing it flat-out refuses is wet feet. Set it in fast-draining ground, keep water off the leaves, and give it space and airflow, and it'll stay healthy and trouble-free for decades. Pack it in tight or leave it sitting in soggy soil, though, and all that toughness turns into blight and root rot.

Care

The short version: full sun, soil that drains fast, and barely any water once it's settled. Forget the rich beds and constant watering, leave each plant room to sprawl, and let it dry right out between drinks.

Light

Creeping juniper craves full sun, and the more the better. Good sun keeps the mat tight and the color honest, while shade thins things out and rolls out the welcome mat for the blight that loves damp, crowded growth.

Water

Once it's settled it's very drought tolerant and only wants a drink every 10 to 21 days, maybe less. Water deep but seldom, let the soil dry right out in between, and keep the hose off the foliage, because wet leaves are what kick off tip blight.

Soil

Above everything else, hand it fast-draining soil, be it sandy, rocky, or just plain poor. It happily takes a broad pH band from 5.5 to 8.0 and copes with lean ground, but it simply can't live where things stay wet.

Temperature

Talk about a tough evergreen, this one's hardy from -40°F to 100°F (-40°C to 38°C). Savage winters and roasting summer heat barely register, which is exactly why it thrives on exposed banks that would do in something more delicate.

Humidity

Creeping juniper likes low humidity and dry air drifting around the foliage. Still, damp air is the problem here, so the trick is never to pile on moisture but to open the plant up so air can flow right through.

Feeding

Feeding it is almost beside the point. A light balanced or slow-release fertilizer in spring only earns its keep when growth has stalled, and a plant sitting in average soil can coast for years on nothing whatsoever.

Pruning

Wait for dry weather, then clip out any dead, diseased, or blight-killed tips, going several inches past the damage into healthy wood and cleaning your blades between cuts. Thin the mat every so often to open it up and keep air drifting through the middle.

Repotting

Repotting is rarely on the menu, since most of these plants spend their whole lives right in the ground. If yours is in a container, keep an eye out for roots circling or pushing out the drainage holes, water draining straight through, or growth that just stalls.

Size & spacing

Plants hug the ground at 6 to 18 inches (15 to 46 cm) tall yet reach 4 to 8 feet (122 to 244 cm) across. Space them out enough that they can fill in over time without crowding, which keeps air moving and disease in check.

When to plant

Plant creeping juniper in spring or early fall, while the soil's easy to work and the roots have time to dig in ahead of fierce heat or a hard freeze. Small cones show up in late spring, and those blue berry-like ones need two whole seasons to ripen. There's nothing to harvest, so really the timing's all about handing the roots 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

Just about every juniper headache comes down to two culprits: foliage that won't dry off and soil that won't drain. Catch the early clues on the tips, the inner branches, and the roots, and you can jump in before one rough patch takes over. Find the match below, then act while there's still time to help.

Severe

The whole thing thinning as roots turn brown

Soggy ground is what triggers Phytophthora root rot, and it turns healthy white roots a sickly reddish-brown until the top of the plant starts to starve. No spray is going to bring rotted roots back, sorry to say. Let things dry out, dig up anything that's too far gone, and put it back somewhere the water actually moves through.

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

Twig ends going brown and fading away

What you're seeing is tip blight, and a couple of different fungi can be behind it once foliage hangs onto moisture. Phomopsis goes for the soft spring and summer flush, and Kabatina turns up on older, beat-up tips by late winter. Wait for a dry day, clip the dead tips off well into living wood several inches down, and wipe the blades clean after each snip.

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

Washed-out, spotty foliage with a bit of webbing

Speckling plus webbing usually means spider mites, and they multiply quick on plants that are hot, dusty, and already stressed. Funny enough, they hit hardest during the cooler runs of spring and fall. Knock them loose with a firm jet of water first, and only bring out insecticidal soap or oil if they won't quit.

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

Little silk bags swinging from nibbled branches

Those hanging pouches are bagworms, caterpillars that live and feed tucked inside a silk case they've woven from snippets of the juniper itself. Every bag is loaded with eggs that ride out winter and become next year's batch. Pluck the bags off all through winter and into early spring, and hit any young larvae with Bt when 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

Pale, tiny scales with a sticky, sugary film on needles

Little white or gray bumps clinging under the needles are juniper scale, and these sap-feeders leave foliage washed-out and gummy with honeydew. Hit them with a dormant oil spray in late winter and you smother them before they really get rolling. Then catch the crawlers come spring, and an insecticide wraps it up.

Fix:

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

Brown lumps pushing out orange jelly in spring

Those galls are cedar-apple rust, a fungus that can't finish its cycle without an apple or crabapple growing somewhere close by. The firm brown bumps puff out into vivid orange tendrils whenever spring turns wet. Cut the galls away, and the real fix is just not setting junipers near apples and crabapples to begin with.

Fix:

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

Brown, dead wood packed inside the crowded mat

Once the canopy thickens up, the middle of the plant gets starved of light and air, so the inner branches quietly give out while the outer layer keeps right on growing green. This is about where it's planted and how packed it is, not a disease at all. Open it up by thinning, pull the dead wood on a dry day, 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

Creeping juniper is an easy plant to live with around the house and yard. It doesn't appear on the ASPCA toxic-plant lists, and the most it tends to do is leave a pet with a mild stomach upset after eating a lot of the aromatic berries or foliage. The real annoyance is that prickly foliage, which can scratch sensitive skin, so pop on gloves when you prune.

Safe for

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

Cats Caution

Mostly fine to have nearby. If a cat munches through a lot of the scented foliage or the berries, the volatile oils might leave it with a slightly queasy belly, so it's smart to keep them off the plant.

Dogs Caution

A quick sniff won't hurt a thing. Down a bunch of the berries or foliage, though, and a dog might drool, throw up briefly, or have a loose stool for a bit, all of which sorts itself out.

Horses Caution

Nibbling a stray sprig here and there is harmless, but a big helping of the berries and resinous oils can upset a horse's stomach, so keep them from grazing it hard.

Rabbits Safe

Nothing to worry about with rabbits. The thick, prickly foliage just isn't tempting, so they usually walk right past it.

Livestock Safe

Cattle, goats, and sheep can graze the same field with no problems, because that sharp, resinous foliage hardly ever tempts them to take more than a taste.

Birds Safe

Totally fine for birds. They'll happily eat the blue cones and spread the seed around as they go.

People Safe

Fine to plant and handle, and a few juniper berries even show up as a cooking spice. That prickly foliage can scratch or bother sensitive skin, though, so slip 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

Almost every creeping juniper you'll buy is a named cultivar picked for its foliage color and just how flat it grows. Here are the ones you're most likely to come across.

Wiltonii (Blue Rug)

It lays down an extremely flat carpet of silvery blue-green foliage that hugs the ground.

Bar Harbor

A quick-spreading, low grower with feathery blue-green foliage that warms to a mauve or purplish cast through winter.

Plumosa (Andorra)

Its soft, mounding gray-green foliage shifts to a clear plum-purple as soon as the cold arrives.

Mother Lode

A Wiltonii offspring that wears golden-yellow foliage on the same dead-flat, low-lying mat.

Lime Glow

Vivid lime to golden foliage builds a low, vase-shaped mound that picks up bronze tones once winter hits.

How to propagate

There are three ways to make more creeping juniper, and which one suits you really comes down to how patient you are and whether the new plants have to match the parent exactly.

Stem cuttingsModerate

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

Want a named cultivar to stay exactly true? Cuttings are how you do it. Pull semi-hardwood cuttings somewhere between late fall and winter, dust them with rooting hormone, and be patient, since juniper roots slowly and can need several weeks to a few months to grab hold.

LayeringEasy

Spring through summer · One or more seasons

Layering just leans into what the plant already does, since those trailing branches put down roots on their own anywhere they touch soil. Pin a low branch to the ground from spring through summer, then let it settle in for a season or more before you snip it loose.

SeedDemanding

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

Seed is the tough route, really one for the patient gardener. It has to go through cold stratification first, then it sprouts slow and patchy across a year or more, and on top of that it won't give you a cultivar true to type.

Myths

Myth

One touch or bite of creeping juniper is enough to make a cat or dog seriously ill from poison.

Reality

You won't find Juniperus on ASPCA toxic-plant lists, and it's usually counted as non-toxic. At worst, eating a lot of the aromatic foliage or berries causes a mild, self-limiting stomach upset instead of anything genuinely dangerous.

Myth

Junipers really want moist, fertile ground and are happier when you water them a lot.

Reality

This is a drought plant through and through, and it wants ground that lets water run right through. Wet, heavy, or overwatered ground is what brings on Phytophthora root rot, which is far and away the most likely thing to finish it off.

Sources