Evergreen

Evergreen is a habit, not a plant

Evergreen describes what a plant does with its leaves rather than what kind of plant it is, and the category covers two groups that behave differently enough that they are worth separating before choosing anything.

Needled evergreens are conifers: fir, spruce, pine, yew and hemlock. A third group sits alongside them with scale-like rather than needle-like foliage, including arborvitae, juniper and false cypress.

Broadleaf evergreens keep ordinary leaves through winter: boxwood, rhododendron, azalea, mountain laurel and holly.

That split predicts most of what you need to know. Broadleaf evergreens generally want more shelter and more acidic soil, and they suffer more visibly in a hard winter, because a wide flat leaf loses water faster than a needle does.

Evergreen does not mean permanent leaves

Every evergreen sheds. It just does not shed everything at once, which is why the plant is never bare.

The practical consequence catches people every autumn. A flush of brown needles deep inside an otherwise healthy conifer is the plant dropping its oldest interior foliage, and it is seasonal rather than a disease. Browning at the tips and on the outside of the plant is the pattern that indicates a problem.

Knowing which is which saves a great many unnecessary treatments.

Evergreen shrubs and bushes, by the job they do

The concept above is only useful once it turns into named plants with mature sizes attached, because size at maturity is what decides whether an evergreen is an asset or a problem in ten years. These are the groups people are usually choosing between.

Small and compact evergreen shrubs

For foundation planting, low hedging and edging, where the constraint is that the plant must stay small without annual shearing.

Plant	Mature size	Notes
Dwarf English boxwood, Buxus sempervirens Suffruticosa	2 to 3 ft tall, 2 to 4 ft wide	Very slow. The classic low hedge and edging box
Boxwood Little Missy	2 ft tall and wide	Compact and rounded, and slow enough to need almost no pruning
Boxwood Green Gem	2 ft tall and wide	For containers and edging. Hardy to zone 4, as are Green Mound and Chicagoland Green
Juniper San Jose	10 to 12 in tall, spreading 5 to 6 ft	Very dwarf and wide, gray-green
Compact Pfitzer juniper	To 3 ft tall, 3 to 5 ft wide	Mass plants as a low screen or foundation planting
Juniper Old Gold	3 ft tall, 5 ft wide	Slow and spreading
Oregon grapeholly, Mahonia aquifolium	3 to 4 ft	Broadleaf. Wants a sheltered, shady spot in moist well-drained acid soil. Winter wind or sun damages the foliage
Inkberry, Ilex glabra	3 to 8 ft depending on variety	Broadleaf native holly. Partial shade to full sun, moist acid soil

The pattern in that table is worth reading. Almost every genuinely small evergreen is small because it is slow, and slow is what keeps it small. A fast shrub sold as compact is compact only in the pot.

Evergreen ground cover

The spreading junipers do this job better than anything else in full sun, and the numbers explain why: they are measured in inches of height against feet of spread.

Plant	Height	Spread	Notes
Creeping juniper Wiltonii	4 to 6 in	6 to 8 ft	Blue foliage turning mauve in winter
Shore juniper Blue Pacific	1 to 1.5 ft	6 to 8 ft	Dense blue-green. Tolerates salt and drought
Japanese garden juniper Nana	2 to 2.5 ft	10 to 12 ft	Bluish-green and deer resistant. Good on slopes and in rock gardens
Parsons juniper	2 to 3 ft	10 ft	Salt and heat tolerant, gray-green scale-like foliage

Junipers as a group want full sun and well-drained soil, take heat and drought once rooted, and need regular water only until they root. Space them for air movement: crowded junipers hold still damp air and that is what brings on the fungal problems they are prone to.

Dwarf and narrow evergreen trees

Where the constraint is width rather than height, which is most residential planting. A columnar tree gives the vertical line without the footprint.

• Emerald Green arborvitae and Steeplechase, compact pyramidal forms that sit in scale with a house rather than dwarfing it.
• Columnar Colorado spruce, Picea pungens var. glauca Fastigiata: 15 feet tall and about 3 feet wide, slow growing, full sun.
• Spartan Chinese juniper: 15 to 20 feet tall and 5 feet wide, dark green.
• Taylor eastern red cedar: 20 to 25 feet tall and only 4 feet wide, dark blue-green. About as narrow as an evergreen tree gets.

For larger broadleaf work, Meserve hybrid hollies run 5 to 10 feet in moist, well-drained, slightly acid soil, and both they and boxwood do best on a protected site. Iowa State makes the siting recommendation concrete: the east side of a building is often the right place, because it gives morning light without the winter afternoon sun and wind that cause the desiccation injury described below.

Evergreen shrubs for clay soil and poor drainage

This is a real constraint rather than a preference, and the honest answer has two halves: pick differently, and plant differently.

On the plant side, most of the reliable evergreens want drainage. Junipers demand sharp drainage and will not tolerate a wet site at all. Boxwood wants moist but well-drained ground at a neutral to slightly alkaline pH. Rhododendrons and their relatives need drainage as much as they need acidity. Arborvitae is the exception that people plant for exactly this reason: it takes clay and wet ground better than the rest of the group. Inkberry, which wants moist acid soil, is the broadleaf equivalent.

On the planting side, Clemson is specific and the advice is counterintuitive enough to be worth stating plainly.

• Plant high. In poorly drained or compacted soil, set the top of the root ball 2 to 4 inches above the surrounding grade and build soil up around the sides of the ball, never over the top of it.
• Dig wide, not deep. Two to five times the width of the root ball, and the wider the better.
• Do not amend the backfill of an individual hole in clay. Backfill with the same unamended soil that came out of it. Amending one hole in heavy ground creates a pocket that holds water and that roots are reluctant to leave.
• Notch the sides of the hole. A smooth, glazed wall in clay acts as a barrier and encourages roots to circle inside the hole instead of moving into the native soil.
• Amend by the bed, not by the plant. Where several shrubs are going in, work organic matter through the whole area at no more than 10 to 20 percent by soil volume, or raise the bed 8 to 12 inches.

Evergreen flowers, grasses and vines

The evergreen habit is not limited to shrubs and conifers, and the other three groups solve problems that shrubs cannot.

Evergreen flowers in a garden context nearly always means the flowering broadleaf evergreens: rhododendron, azalea, mountain laurel and camellia. Rhododendron is the group most people mean, and it comes with conditions: Catawba rhododendron wants morning sun with afternoon shade and well-drained acid soil at pH 4.5 to 5.5, and it fails on windy exposed sites. PJM types run 4 to 6 feet and the Marjatta hybrids 2 to 6, and both want shelter from winter sun and wind.

Evergreen grasses are mostly sedges rather than true grasses, and Carex is where to look for a plant that holds its foliage through winter in shade.

• Carex morrowii, Japanese sedge, in variegated forms: Ice Dance with white leaf edges, Variegata with a wide yellow center stripe, Goldband striped white and green, and Everglow with cream margins that turn orange in winter.
• Carex oshimensis Everillo, bright lime green, and Eversheen with a lime stripe down the leaf.
• Carex plantaginea, seersucker or plantain sedge, native to the eastern United States, with inch-wide crinkled, pleated bright green foliage.
• Carex cherokeensis, arching and evergreen to semi-evergreen.

Among true grasses, blue oat grass, Helictotrichon sempervirens, holds a dense two-foot mound of stiff silvery blue blades, and tufted hair grass, Deschampsia cespitosa, forms a foot-high clump of fine dark green leaves.

Evergreen clematis means Clematis armandii, the Armand clematis, which is the answer for an evergreen flowering vine in a mild climate. It is hardy in zones 7 to 9, climbs 15 to 30 feet and spreads 10 to 15, and carries clusters of two-inch creamy white flowers with a strong vanilla scent from March into May against glossy dark green leaves. It flowers on old growth, so it is pruned immediately after flowering and never in late winter; if it gets away entirely it can be cut to the ground and will regrow from the base. Outside zone 7 it is not a candidate.

On varieties, this is a case where the species does the work and the named forms are a minor matter. Clemson describes it flowering from late February or early March into early April, with four, five or even six petals to a flower, attaching itself by hooks and tendrils in the leaf stalks rather than by twining stems, and carrying essentially no pests. Give it part shade and rich woodsy soil, mulch with leaf litter to keep the roots cool, and water it through drought. Named cultivars are sold, but the extension sources this database works from do not distinguish them, so this entry records the species and leaves the varieties as not researched rather than describing differences it cannot verify.

Landscaping with evergreen shrubs and trees

The design question is separate from the plant list, and it comes down to what the plant is being asked to do. Four jobs cover almost all of it.

• Structure. A few evergreens hold the shape of a bed through the months when everything else is bare. This is the one job nothing else does, and it argues for placing them where they are seen from the house in winter rather than where they look best in June.
• Foundation planting. The commonest use and the commonest mistake. The shrub that fits under a window at planting fits under it in fifteen years only if its mature size says so, and no amount of shearing makes a large shrub into a small one. This is where the slow, genuinely dwarf boxwoods and junipers in the table above earn their price.
• Screening and boundary. Covered further down, and the rule is mature width rather than height.
• Accent. A single columnar tree gives a vertical line that a mixed border cannot produce on its own. Narrow forms such as Taylor eastern red cedar at 4 feet wide do this in spaces where a conventional tree would not fit at all.

Two constraints run under all four. Match the plant to the site rather than amending the site to the plant, because an evergreen is a permanent planting and a mismatch shows for decades. And vary the group: a bed of one species in one size reads as a hedge whatever the intention, and a single pest can empty it.

On hardiness, junipers as a group cover roughly zones 3 to 9 depending on cultivar, which is the widest range in this article and part of why they turn up in so many landscapes. Among the boxwoods the hybrids Green Gem, Green Mound and Chicagoland Green are hardy to zone 4, while the English forms want milder ground and a sheltered spot.

Chinese evergreen is a different plant entirely

Worth separating out, because the name sits inside this one and the plant has nothing to do with any of the above. Chinese evergreen is Aglaonema, a tropical foliage houseplant. It is not hardy, it is not a shrub, and it will not survive a winter outdoors anywhere in the continental United States.

It is worth knowing on its own terms, since it is one of the most durable houseplants sold, tolerating poor light, dry air, air conditioning and drought. Solid green cultivars grow in genuinely low light; the variegated ones need more, and the lighter the leaf, the more light it wants. Keep the soil slightly moist rather than letting it dry out, feed every four weeks in growth and every six in winter, and keep it above 50°F, since it is sensitive to chilling below that. It contains calcium oxalate crystals and is toxic to dogs, cats and horses, causing mouth pain, drooling and difficulty swallowing, and the sap irritates skin. Propagate it from stem cuttings with at least five leaves.

Winter burn, which is the characteristic failure

This is the single most common complaint about evergreens and the mechanism is worth understanding, because it explains why the treatment is watering in November rather than anything applied in spring.

Evergreens keep transpiring through winter. When the ground is frozen the roots cannot replace what the foliage loses, while winter sun, wind and temperature swings keep drawing moisture out. The plant browns on the exposed side, typically west and south-west, and the damage appears in late winter rather than during the cold itself.

1. Water thoroughly in late autumn

   Before the ground freezes. A plant that goes into winter fully hydrated has a reserve; one that goes in dry does not.

2. Site away from the most exposed corner

   Wind and reflected sun off a wall or a driveway are what turn a cold winter into a damaged plant.

3. Do not feed in late summer

   It pushes soft growth that has not hardened before the first freeze.

4. Screen new plantings

   Burlap screens and temporary shade are described as particularly valuable for newly established plants, which have neither the root system nor the hardened tissue to cope.

5. Wait before cutting damaged growth

   Brown foliage in March often has live buds behind it. Assess in late spring, once new growth shows what actually survived.

Using evergreens for screening

Screening is the most common reason people buy them, and it is also where the most expensive mistakes happen.

Mature width decides the spacing, not the size in the pot. Arborvitae is the standard example: the plain species reaches 40 to 60 feet, while the narrow cultivar people actually want stays around 12, and unnamed stock is a lottery.

Two structural rules apply. Stagger two offset rows rather than planting a single line, so one loss does not become a gap. And accept that conifers do not regrow from bare interior wood, which means a screen that outgrows its space cannot be reduced, and any damage at a given height is permanent.

A mixed screen of several species is more work to plan and considerably more robust, because a single-species hedge is one pest or disease away from a complete gap.

Deer decide which evergreens are possible

This is not a minor consideration in much of the country, and the species differ sharply.

Arborvitae is the problem case: deer are very fond of it and do considerable feeding damage, eaten to a clean horizontal line at browsing height, and because the plant does not regrow from bare wood the damage is permanent. Yew is similarly favored.

Junipers are largely left alone, and the reason is mechanical: the foliage is sharp or prickly. Spruce is also generally avoided for the same reason.

In deer country, that single fact is worth more than any repellent program. Choosing a prickly-foliaged evergreen for a boundary is a decision that keeps working every winter without maintenance.

Matching the species to the site

The site conditions worth checking before choosing are the ones evergreens differ most on: whether the ground stays wet, whether it goes very dry, and how much shade the position gets.

Arborvitae tolerates wet sites and clay. Junipers want sharp drainage and full sun and rot in wet ground. Yew and hemlock tolerate real shade, which very few conifers do. Boxwood and rhododendron want shelter and acid soil, and rhododendron in particular is intolerant of both alkaline ground and winter wind.

Getting that match right removes most of the maintenance, which is the argument for spending an evening on selection rather than a decade on rescue.

Frequently asked questions

Why is my evergreen brown inside?

Usually normal. Evergreens shed their oldest interior foliage rather than keeping every leaf forever, so a flush of brown deep inside a green plant in autumn is seasonal. Browning at the tips and on the outside is the pattern that signals a problem.

What causes winter burn and can I prevent it?

The plant keeps transpiring while frozen ground stops the roots replacing the water, and sun and wind accelerate the loss. Water deeply in late autumn before the ground freezes, avoid exposed corners, skip late-summer feeding, and screen new plantings with burlap.

Which evergreens do deer avoid?

Junipers and spruce, because the foliage is sharp or prickly. Arborvitae and yew are the ones deer are very fond of, and since conifers do not regrow from bare wood, that damage is permanent.

How far apart should I plant a screen?

By mature width, which means the cultivar name has to be known first. Stagger two offset rows rather than a single line, so a single loss does not leave a permanent gap.

Can I cut an overgrown evergreen back?

Not into bare wood. Conifers do not regrow from it, so a hard cut leaves a permanent hole. Light regular trimming keeps a hedge in bounds; letting it outgrow the space is not recoverable. Broadleaf evergreens such as boxwood and holly are more forgiving.

Companion plants