Juniper Growing Guide: Choose Ground Cover, Shrub or Tree, Then Your Species for Zones 3–9 (and How Far Cedar-Apple Rust Travels)

A juniper’s shape is settled before you plant it. The species and cultivar decide whether you get a 6-inch mat, a 6-foot mound or a column that tops 20 feet, and pruning can’t change that later, because junipers generally can’t regrow from bare wood. That makes “which juniper?” the one decision that matters, and it’s why this guide works in the order the decision runs: habit first, then a species for your USDA zone, then three problems that come up again and again in the extension sheets: wet soil, winter desiccation and cedar-apple rust.

The short version

• Habit: Clemson Extension gives ground covers and small shrubs a mature height of 6 inches to 6 feet, large shrubs about 15 feet and trees up to 60 feet. Choose by the space you have at maturity, not by the size in the pot.
• Zone: Clemson Extension says most species are adapted to USDA zones 3 to 9, though few species cover the whole span: in our table only creeping juniper and eastern redcedar do. Creeping juniper is the only ground cover in our species table hardy to zone 3, and eastern redcedar is listed down to zone 2.
• Pruning: cut only into green foliage. Junipers have no dormant buds on older wood, so a cut into bare wood leaves a permanent gap.
• Site: full sun and drainage that lets water leave. Clemson calls Phytophthora root rot one of the most destructive juniper diseases in South Carolina, and says it is most common in poorly drained soil.
• Apples nearby: none of the university and botanical-garden sources we reviewed gives a distance that is safe. Plant resistant apples and crabapples instead of counting feet.

Which juniper habit fits the job: ground cover, shrub or tree?

Pick the habit from the space and the job, because the three habits span roughly 6 inches to 60 feet. Clemson Extension’s juniper factsheet gives ground covers and small shrubs a mature height of 6 inches to 6 feet and a spread of 6 to 20 feet; Clemson’s companion sheet for large junipers puts large shrubs at about 15 feet and trees at up to 60 feet.

The height and spread ranges in this table are our grouping of the cultivar figures in the Clemson and NC State sheets (the 3-foot lower bound on ground-cover spread comes from NC State’s profiles); Clemson’s outer limits are 6 inches, about 15 feet for large shrubs, 60 feet for trees and 20 feet of spread, and individual cultivars vary.

In short, a juniper is a ground cover, a shrub or a tree depending on which one you buy, not on how you trim it. Chinese juniper shows how loose the labels are: NC State Extension lists the species at 50 to 60 feet tall, while Clemson notes that its cultivars range from low spreading ground covers and dense shrubs to upright trees. The habit belongs to the cultivar on the tag, not to the species name. Our creeping vs. skyrocket juniper comparison works through that choice for the two extremes.

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One more thing the tag may not tell you: most junipers are dioecious, with male and female plants separate. Males make pollen cones, and females make the round, fleshy cones that resemble small berries (Clemson). If the cones are what you’re after, our juniper berries species guide covers which species the berries come from.

Which junipers suit USDA zones 3 to 9? The species ladder

Clemson Extension says most junipers are adapted to USDA zones 3 to 9, though few species cover that whole span: in the table below only creeping juniper and eastern redcedar do. NC State Extension’s Plant Toolbox lists eastern redcedar down to zone 2 and shore juniper only from zone 6, so the zone column below decides more than the photo does.

The takeaway: of the eight junipers in this table, creeping juniper, Rocky Mountain juniper and eastern redcedar are the zone 3 options (redcedar goes to zone 2), while Rocky Mountain juniper stops at zone 7 and ‘Blue Star’ at zone 8. Creeping, Japanese garden ‘Nana’, Pfitzer, Chinese, shore juniper and redcedar all reach zone 9.

Treat the sizes as ranges, because sources disagree on the same name. NC State puts ‘Nana’ at 6 inches to 1 foot tall and 3 to 6 feet wide; Clemson lists it at 2 to 2½ feet tall and 10 to 12 feet wide. Measure against the cultivar tag, then leave room for the larger figure. Also note that ‘Bar Harbor’, ‘Nana’ and shore juniper are among the cultivars Clemson flags as highly susceptible to root rot on wet sites; the planting section below explains why.

A few zone-specific cautions from the extension sheets:

• Zones 3 to 4: creeping juniper is the only ground cover in the table hardy to zone 3. ‘Skyrocket’ is rated for zones 3 to 7 by Texas Tech’s plant directory, which adds that it will not withstand the humidity and heat of the deep South.
• Zones 5 to 6: every juniper in the table is listed for zone 6, and all but shore juniper are listed for zone 5. NC State warns that shore juniper can suffer winter injury in colder climates when temperatures drop to -10°F.
• Zones 7 to 9: Clemson says Rocky Mountain juniper cultivars are intolerant of high humidity and more disease-prone than eastern redcedars (a general statement; for cedar-apple rust specifically, see the rust section below), and that ‘Blue Star’ tends to be short-lived in the Southeast. For that cultivar, see our Blue Star juniper care guide.

Why can’t a juniper regrow from old wood? The pruning rule behind everything else

Junipers can’t be cut back into bare wood because they have no dormant buds on older wood, so nothing sprouts behind the cut. Kansas State’s pruning bulletin says it directly: junipers, pines and spruces “do not have dormant buds on older wood, so they do not resprout behind pruning cuts,” while most broadleaved shrubs resprout vigorously from the many dormant buds along their stems.

The New York Botanical Garden’s plant information service draws the same contrast. Hollies and privet can be cut to the ground and sprout back from dormant buds; junipers and other narrow-leaved evergreens will not come back after that treatment. Colorado State factsheets, quoted in an Ask Extension answer, give the working version: new growth comes only from the growing tips, so a shrub pruned back to bare wood will have a permanent bare spot.

It helps to picture each branch in two parts: a green outer zone that carries foliage and can make new shoots, and an inner zone of bare wood that can’t. Every cut is either into the first zone or it isn’t.

The practical rules that follow from that mechanism:

• For your main pruning, take no more than a third of each branch. That is the limit given in the Ask Extension answer from Colorado’s Weld County Master Gardeners. The Colorado State factsheets it quotes add that junipers growing in shade tolerate pruning poorly because they grow slowly.
• Prune in late winter or early spring, before new buds break. NYBG says junipers make new growth in spring and fall, and that light touch-up in summer is fine. Kansas State says light pruning, removing no more than 10 percent of the plant, can be done at any time of year.
• Start small. NYBG suggests beginning the second year after planting and pruning a little each year.
• Replace instead of rescuing. For a badly overgrown juniper, the Ask Extension answer suggests digging it out and replacing it, and the Colorado State factsheets it quotes suggest a smaller cultivar or another species.

That last rule is why the habit table comes first. NYBG’s own advice is to research the mature size before you plant, so the realistic tools afterward are trimming back to a side branch, which Kansas State lists junipers among the plants suited to, and, for a badly overgrown plant, replacing it. If you’re training a juniper as a bonsai, that’s a different practice from landscape pruning; see our juniper bonsai care guide.

Where and when to plant: sun, drainage and timing

Plant junipers in full sun and well-drained soil, because wet soil turns a drought-tolerant plant into a root-rot casualty. Both of Clemson’s juniper factsheets list full sun and well-drained soil, and NC State’s Plant Toolbox profiles for the eight junipers in the table above all list good drainage.

The reason is Phytophthora root rot. Clemson describes it as a soil-borne water mold that thrives in saturated soil and infects the roots so they can no longer take up water and nutrients, which is why a rotting juniper can look like a thirsty one. The symptoms are gradual decline, thinning foliage, branches dying one at a time and roots with reddish-brown centers. Once symptoms show, Clemson says the disease can’t be cured, so prevention is the whole strategy: avoid spots that stay wet or flood, avoid heavy clay, plant in raised beds where drainage is poor (except in deep sandy soils), or work ground pine bark, not sawdust or peat, into the soil to a depth of 8 to 12 inches.

Clemson also names the junipers it considers highly susceptible to this rot, and all of them are ground covers: ‘Andorra’ (also sold as ‘Plumosa’), ‘Bar Harbor’, ‘Parsoni’, ‘Sargents’, ‘Shore’ and Juniperus procumbens ‘Nana’. The low mat that makes a ground cover attractive is the habit to keep away from soggy corners.

For timing, NYBG says evergreen trees should go in a bit earlier in fall than deciduous trees, about 4 to 6 weeks before the expected first frost, so the roots can start developing before winter. NYBG writes this mainly for large balled-and-burlapped trees and says small container-grown plants allow more leeway. In cold climates (zones 1 to 3) NYBG recommends early spring once the ground has thawed, and in warm climates (zones 9 and 10) fall. Space plants by their mature spread: Clemson notes that good airflow reduces prolonged foliage wetness, which contributes to fungal infections, and that correct spacing means you prune healthy branches less often.

How often should you water a juniper, from planting to established?

Water a new juniper on a schedule for about three growing seasons, then very little, because Kansas State’s watering bulletin treats establishment as a three-season job and Clemson says established junipers need only minimal supplemental irrigation. Kansas State’s figures are written for trees and large shrubs; it says smaller plants may need less water, but enough to moisten the entire rootball.

Check before you water. The University of Maryland Extension advises digging down about 6 inches and watering only if the soil is dry there, and warns that many people have inadvertently drowned newly planted trees by watering them too often. Kansas State explains the mechanism: soil that stays wet depletes oxygen around the roots, and the resulting “wet wilt” looks like the wilt caused by dryness, but adding water doesn’t help.

Why does a drought-tolerant juniper turn brown in winter?

Winter burn is a water-balance problem. A winter-desiccation factsheet hosted by Maine’s agriculture department explains that it happens when evergreen foliage loses more water than the roots take up. Needles keep losing water through winter, faster on warm, sunny or windy days, and if the soil is frozen or dry the roots can’t replace it. The needles die but can stay green until spring, so the browning may show up months after the damage, often on the side facing the wind or a south- or west-facing wall. The factsheet names junipers among the plants vulnerable to winter drought damage.

The fix is a fall soak when rain has been short: the factsheet’s guidance is to water well in fall until the soil freezes, keeping shrub soil slightly moist to 18 inches, and to water again during dry winter spells only when the air is above freezing and the soil isn’t frozen. The University of Maryland Extension agrees: it says evergreens should be watered deeply in fall before the ground freezes if precipitation has been insufficient, and notes that they lose water in winter especially above 40°F on sunny, windy days.

Not every brown juniper has winter burn. Clemson cautions that browning tips and dieback can come from drought, overwatering, root injury or fungal disease, so look at the pattern before you treat.

Treating the wrong problem is the common mistake. Clemson says twig-blight fungicides should be applied before infection occurs and that fungicide will not cure a plant that already has Phytophthora root rot. Winter burn is a water problem, so there is no fungus to spray. Our guide to juniper turning brown covers the fungal causes in more detail.

How does cedar-apple rust move between junipers and apples, and how far apart is far enough?

None of the university and botanical-garden sources we reviewed gives a distance that is safe; they describe how far spores travel, not a distance at which infection stops. Illinois Extension says most infections happen within several hundred feet of the source juniper but that spores may be carried several miles; Cornell’s apple disease database puts typical spread at about a mile or less; Clemson says up to half a mile from juniper to apple and within two miles on the way back; Iowa State says as far as two miles; and NYBG says up to five.

The reason distance can’t be a fence is the disease’s mechanism. The fungus Gymnosporangium juniperi-virginianae needs two hosts and takes 24 months to complete one cycle, according to Illinois Extension:

1. On the juniper, a gall (a lump of fungal and plant tissue) swells in rainy spring weather and pushes out bright orange, gelatinous horns that release spores.
2. Wind carries the spores to apple and crabapple leaves. A wet period of 4 to 6 hours at 50 to 75°F is enough for severe infection.
3. Yellow spots appear on the leaves, and by midsummer cup-like structures form on the undersides. Their spores infect junipers from midsummer into early fall.
4. The following spring a gall begins to develop on the juniper. It grows through the summer and is full size by fall, ready to produce horns the next spring.

With spores traveling that far, NYBG warns that removing a host on your own property may not help, because the spores can come from beyond it.

Here is how I’d use the evidence, which is my own synthesis rather than a published rule: treat distance as a dose, not a fence. Closer means more spores; farther means fewer, never none. So spend your effort on resistance:

• Choose the apple side first. Iowa State lists ‘Redfree’, ‘Liberty’, ‘William’s Pride’ and ‘Freedom’ as apples immune to cedar-apple rust, and ‘Jonathan’, ‘Rome’, ‘Wealthy’, ‘York Imperial’ and ‘Golden Delicious’ as susceptible. Its resistant crabapples include ‘Adams’, ‘David’, ‘Donald Wyman’, ‘Indian Summer’, ‘Prairie Fire’, ‘Professor Sprenger’ and ‘White Angel’; it advises avoiding crabapples with serious disease problems, such as ‘Hopa’, ‘Radiant’ and ‘Vanguard’. Our guide to disease-resistant crabapples and apple growing guide cover the fruit side.
• Know which junipers are the problem hosts. Iowa State names eastern redcedar and Rocky Mountain juniper as the susceptible ones, and Clemson says eastern redcedar is the juniper most often affected. But NC State’s profiles also list cedar-apple rust among the problems of creeping, Chinese, Pfitzer, shore and ‘Blue Star’ junipers, so don’t assume other species are immune.
• Pick resistant juniper cultivars where you can. Clemson lists cultivars resistant to both Phomopsis blight and cedar rust, including Chinese juniper ‘Foemina’, ‘Keteleeri’ and ‘Mint Julep’; creeping juniper ‘Plumosa’ (Clemson’s HGIC 1107 lists it as the same plant as ‘Andorra’) and ‘Wiltoni’ (the ‘Wiltonii’ or Blue Rug of the table above); and savin juniper ‘Broadmoor’ and ‘Skandia’. That resistance is to blight and rust, not to root rot, so ‘Plumosa’ (Andorra) still needs the drainage described above. Clemson’s list doesn’t give hardiness zones, so check each cultivar against your zone; the Chinese juniper species, for example, is listed for zones 4 to 9.
• Cut out galls. On small junipers, Iowa State says rust galls can be pruned out in late winter or early spring, by April 1; Illinois says to remove them before the horns form. Iowa State says rust generally does little damage to cedars and junipers, though severe cases can cause twig dieback, and Illinois notes that a gall can kill the twig from the gall to its tip.

Two cousins are worth knowing. Illinois Extension distinguishes cedar-apple rust from cedar-hawthorn rust and cedar-quince rust, which also use junipers as their evergreen hosts but have partly different deciduous hosts, so a rusty hawthorn or flowering quince is not necessarily the same disease.

Do deer eat junipers?

Most junipers rate “seldom severely damaged” on the Rutgers deer list, but not all. Rutgers Cooperative Extension grades plants A (rarely damaged), B (seldom severely damaged), C (occasionally severely damaged) and D (frequently severely damaged). Its list gives A to creeping juniper ‘Prince of Wales’ and Rocky Mountain juniper ‘Moonglow’. It gives B to creeping juniper, Chinese juniper, Pfitzer juniper, Savin juniper, ‘Blue Star’, Japanese garden juniper ‘Nana’ and eastern redcedar. Shore juniper is the outlier at C.

Rutgers says plants rated C and D are often preferred by deer and “should only be planted with additional protection such as the use of fencing, repellents, etc.” It also notes that success of any of these plants “will depend on local deer populations and weather conditions.” Treat a B rating as better odds, not a guarantee.

Juniper care calendar: what to do each season

The calendar below collects the timing from the sections above into one place; the tasks are the extension recommendations quoted earlier, ordered by season. Your own dates will shift with your zone.

Juniper FAQ

Can you cut a juniper back to bare wood?

Generally not. Junipers have no dormant buds on older wood, so a cut into needle-free wood doesn’t resprout behind the cut and leaves a permanent bare spot. Prune only into green foliage, taking no more than a third of each branch. Kansas State adds that light pruning, no more than 10 percent of the plant, can be done at any time of year.

How far should junipers be from apple trees?

None of the sources we reviewed gives a safe distance. Illinois Extension says most infections occur within several hundred feet but spores may travel several miles, and others say up to a mile, two miles or five miles. Plant resistant apple and crabapple cultivars instead of relying on distance.

Which junipers grow in zone 3?

Of the eight junipers in the species table, NC State Extension lists creeping juniper for zones 3 to 9, Rocky Mountain juniper in zones 3 to 7 and eastern redcedar in zones 2 to 9. ‘Skyrocket’ is rated for zones 3 to 7 by Texas Tech.

How often should you water an established juniper?

Very little. Clemson says established junipers need only minimal supplemental irrigation, and the University of Maryland Extension says large, mature shade trees and shrubs can be left alone unless the drought is severe, they wilt or their roots were recently disturbed. Soak evergreens in fall, if rain has been short, until the soil freezes.

Why is my juniper brown after winter?

A common cause is winter desiccation: foliage lost water faster than frozen or dry soil could replace it, and the damage shows in spring, often on the windward side or the side facing a south- or west-facing wall. Check the pattern against the diagnostic table above before treating for a disease.

Are junipers deer-resistant?

Mostly. Rutgers rates most junipers B (seldom severely damaged) and shore juniper C (occasionally severely damaged), with local deer numbers and weather affecting the result.

Sources

1. Clemson Cooperative Extension. Growing and Using Juniper (Juniperus spp.): Groundcovers and Small Shrubs, HGIC 1107. Home & Garden Information Center
2. Clemson Cooperative Extension. Growing and Using Juniper (Juniperus spp.): Large Shrubs and Trees, HGIC 1068. Home & Garden Information Center
3. Clemson Cooperative Extension. Juniper Diseases and Insect Pests. Home & Garden Information Center
4. Kansas State University Research and Extension. Pruning Shrubs, MF2998
5. Kansas State University Research and Extension. Watering Newly Planted and Young Trees and Shrubs, MF2800
6. New York Botanical Garden, Mertz Library. When and how do I prune mature junipers?
7. Ask Extension. Pruning overgrown junipers (Weld County, Colorado Master Gardeners, quoting Colorado State University factsheets). Question 465307
8. New York Botanical Garden, Mertz Library. When is the best time to plant trees?
9. Illinois Extension. Cedar Apple Rust. Plant Problems
10. Iowa State University Extension and Outreach. Cedar-Apple Rust. Yard and Garden
11. Cornell University. Fact Sheet: Cedar Apple Rust. Database of Apple Diseases
12. New York Botanical Garden, Mertz Library. Can you tell me how to treat my juniper trees for cedar-apple rust?
13. Maine Department of Agriculture, Conservation and Forestry (host of the factsheet). Seasonal Landscape Problems: Winter Desiccation Injury
14. University of Maryland Extension. Watering Trees and Shrubs
15. Rutgers Cooperative Extension. Deer Resistant Plants
16. Texas Tech University Plant Resources. Skyrocket Juniper (Juniperus scopulorum ‘Skyrocket’). Woody Plant Finder
17. NC State Extension Plant Toolbox: Juniperus horizontalis; Juniperus procumbens ‘Nana’; Juniperus conferta; Juniperus squamata ‘Blue Star’; Juniperus x pfitzeriana; Juniperus chinensis; Juniperus scopulorum; Juniperus virginiana