Green Giant vs. Emerald Green arborvitae: choose for size, not speed

A privacy tree looks conveniently small when it arrives in a nursery pot. The expensive decisions come later: branches pressing against the fence, shade over the patio, or a screen that never reaches the window you wanted to hide. Green Giant and Emerald Green both make dense evergreen plantings, but they are not interchangeable versions of the same tree.

Choose Green Giant for a genuinely large planting area where a tall, broad screen belongs. Choose Emerald Green when a narrower, shorter evergreen fits the job. First measure the space the mature plants will occupy, then choose the spacing and purchase size. Fast growth is useful only after the tree fits. ^{[1] [2]}

This guide takes you from an empty boundary to a measured planting plan. Keep a tape measure, paper, and a photo of the site nearby. The privacy-planting workbook gives you room to record the measurements, compare layouts, and organize establishment care without guessing how many trees to buy.

Compare the mature trees

Green Giant is a hybrid arborvitae; Emerald Green is the cultivar 'Smaragd' of eastern arborvitae, Thuja occidentalis. The useful distinction for a gardener is their eventual scale. NC State lists Green Giant at 40–60 feet tall and 12–18 feet wide. The Morton Arboretum describes Emerald Green at 10–15 feet tall and 3–4 feet wide. Those are landscape reference ranges, not a promise that every tree stops at a particular measurement. ^{[1] [2]}

Size references: ^[1] and ^[2]. The roles and questions are planning guidance derived from those dimensions.

A six-foot fence is not a scale reference for the tree's lifetime. A mature Green Giant rises far above it, while Emerald Green is a more modest element in the same setting. Stand back and imagine the canopy, not simply a line of trunks. A tree that is narrow enough at its base today still needs room for future branches, maintenance access, and the neighboring plants you intend to keep.

Use the upper end of the reference width when checking whether an untrimmed specimen physically fits. For a maintained hedge, record the maintenance commitment separately. Do not quietly replace mature width with the width you hope pruning will hold. Those are two different designs with different amounts of work.

Define the view you need to screen

Start at the place where privacy matters: a dining chair, bedroom window, or seating area. Photograph the unwanted view from that position. Repeat the photograph while standing. A boundary planting that looks opaque from the lawn might not block an elevated window or a view down a slope.

Mark the necessary screening zone on the photograph. Identify whether you need foliage near ground level, at sitting height, or much higher. Also mark views you want to preserve. It is easy to solve one sightline by accidentally removing daylight or a pleasant view from another part of the house.

Write one sentence describing the job. For example: “Screen the neighboring ground-floor patio while leaving the sunny vegetable bed open.” That goal usually calls for a different tree and placement from “Reduce a view of the upper story across a large rear lawn.” Keep the sentence beside your measurements so a sale price or fast-growth claim does not replace the original problem.

Next, walk the proposed row from both sides. Include the space needed to open gates, reach hose connections, clean windows, and maintain the fence. Record existing trees overhead and established roots beneath the row. A planting plan should preserve the functions of the garden, not merely fill every available gap.

Plan the whole boundary first, including mature canopy width, access, and neighboring structures. The comparison here answers the narrower question of which of these two arborvitaes belongs in that arrangement.

Check climate, light, and drainage

Green Giant's NC State profile lists hardiness zones 5–8. Eastern arborvitae has a colder-growing range, with Morton listing zones 3–7 at species level. Treat that species information as context, then check the exact Emerald Green plant and your local conditions. A zone describes winter minimum temperatures; it does not measure drainage, summer heat, wind exposure, or local disease pressure. ^{[1] [2]}

Both choices need a suitable light environment. Full sun is the straightforward location to assess first. NC State notes that eastern arborvitae thins dramatically in full shade, and Green Giant also performs best with good light. A narrow strip underneath a mature canopy is not transformed into a reliable screening site by ordering a narrow cultivar. ^{[1] [3]}

Observe the proposed row at several times on a clear day. Note where direct sun reaches the actual planting positions and where the house, fence, or other trees intercept it. Repeat the observation when seasonal foliage or sun angles substantially change the view. A description such as “bright yard” is less useful than a sketch of the shaded and exposed portions of the row.

Check the soil after substantial rain. Mark places where water remains, where runoff collects, and where the ground stays saturated. A tree tolerating a range of soils is not the same as a tree suited to persistent standing water. Resolve drainage and site suitability before buying; do not attempt to hide a wet planting hole with a better-looking surface layer. ^[4]

Take these observations one segment at a time. A 70-foot boundary might contain a wet corner, a sunny middle, and a deeply shaded end. It does not need one species simply because it is one boundary. Splitting the design around actual conditions is often more practical than forcing a uniform row into incompatible locations.

Separate spacing from setback

Center-to-center spacing is the distance between adjacent trunks along the row. Setback is the distance from a tree's center to a fence, path, wall, or another constraint. Reducing the spacing between trees does not reduce the room the planting needs beside the row.

For an untrimmed tree, half the reference mature width gives an initial canopy-radius estimate. A four-foot-wide Emerald Green extends approximately two feet from its center in a simplified plan. An eighteen-foot-wide Green Giant extends approximately nine feet. Add whatever clearance your actual site needs beyond that simplified canopy edge. This is geometry for planning, not a guarantee of symmetrical growth or a legal setback rule.

For example, placing a broad tree three feet from a fence does not reserve space for a canopy with a nine-foot radius. Its eventual branches would cross that line unless the tree is constrained. The smaller tree is not automatically suitable either: a two-foot canopy radius leaves no working space when its trunk is two feet from the same fence.

Plan two versions of the row on paper. In the first, draw mature canopies at their full reference widths. In the second, draw your intended maintained hedge width. The difference makes the ongoing pruning commitment visible. If the maintained version depends on repeatedly removing most of the natural width, choose a different plant rather than treating that workload as an incidental detail.

Hedge spacing involves intentional canopy overlap, while specimen spacing leaves individual shapes distinct. There is no single center-to-center distance that serves both goals. Your selected cultivar, expected width, acceptable time to closure, and maintenance plan all belong in that decision. Keep nursery planting guidance with the drawing and identify whether it describes a hedge, windbreak, or free-standing specimen.

Do not choose a tight double row simply because a diagram looks denser. Draw the total depth of both rows at maturity, then add access. A staggered layout consumes considerably more ground than a single row. Where the land is narrow, a second row often creates the very space problem you were trying to avoid.

Calculate the tree count correctly

Tree counts fail when the number of trees is confused with the number of gaps. Ten trees in a straight row create nine spaces between their centers. End allowances must also come out of the boundary length before you calculate those spaces.

Use this sequence for a first-to-last-center layout: measure total usable length, subtract the allowance at each end, divide the remaining span by your proposed maximum center spacing, round that number of intervals up, and add one tree. Then divide the actual center span by the number of intervals to obtain equal spacing.

Here is a worked arithmetic example, not a planting recommendation. A boundary is 60 feet long, and the design reserves three feet at each end before the first and last tree centers. The center span is therefore 54 feet. A proposed maximum interval of six feet gives 54 ÷ 6 = 9 intervals. Nine intervals require ten trees, at exactly six feet between centers.

Changing the proposed maximum interval to eight feet changes the calculation. The same 54-foot span divided by eight gives 6.75 intervals. Round up to seven intervals and use eight trees. Equal spacing becomes 54 ÷ 7, or approximately 7.71 feet. Do not round the tree count down and leave an unexplained end gap.

This method assumes you deliberately place trees at both endpoint centers. Another valid design divides the whole planting run into equal planting cells and places one tree at each cell center. That produces different end allowances. Choose one layout method and show the centers on paper rather than mixing the calculations.

Before ordering, mark the proposed centers with temporary markers and walk the site again. Open every gate. Check the mature-width outline against the path. Verify the number against your sketch. This inexpensive rehearsal catches errors that a calculator cannot see, including a forgotten utility box or an irrigation head inside a future trunk position.

Compare speed without buying a deadline

NC State reports that Green Giant can grow three to four feet per year in optimal conditions. “Optimal” matters. That figure is not a promise for a newly delivered tree, a shaded site, or a dry planting strip. Emerald Green is the smaller-scale option, but its purchase size still does not establish a date when your particular row will close. ^[1]

Separate three questions: how quickly the leader grows upward, how quickly the canopy widens, and how soon the planting blocks the view from your chosen position. A height-growth figure answers only part of the first question. A row with visible gaps can be tall without providing the privacy you expected.

Compare purchases using the whole installation, not just the plant price. List the number of trees, delivery arrangements, planting access, mulch, irrigation equipment, and your ability to water the row while it establishes. Buying fewer large specimens and buying more small ones are different designs, not automatically equivalent shortcuts.

Record what you accept in the early years. Temporary screening, an adjusted seating position, or patience with gaps might be part of the plan. Those are clearer choices than crowding a long-lived tree because a mature screen is needed immediately. Plan for the permanent planting first, then solve the temporary view separately.

When the larger tree fits, compare the available Thuja Green Giant arborvitae options. Where the smaller mature footprint is the deciding factor, examine Emerald Green arborvitae. Choose the plant before choosing the size variation.

Account for deer, salt, and exposure

Green Giant is often described as deer resistant; NC State lists resistance to deer, while eastern arborvitae is a browsing plant. Resistance is not a no-damage warranty. Look at existing nearby plantings and local browsing pressure before making an unprotected hedge the sole privacy barrier. ^{[1] [3]}

Draw a second line on the plan for any temporary protection and its access needs. A protection system that touches every outer branch, blocks the path, or cannot be opened for watering has not been integrated into the design. Include its maintenance in the installation decision rather than waiting for the first damaged tree.

Green Giant does not tolerate salt spray or salty soil well. An exposed coastal location or a roadside strip receiving de-icing runoff deserves particular attention. Brown foliage on the road-facing side also has a different investigative starting point from uniform browning across an entire row. ^{[1] [6]}

Winter wind, sun, and dry conditions affect evergreens even when the species is broadly hardy in the region. Record which side faces prevailing exposure and whether autumn soil moisture needs attention. Snow and ice also create structural stresses; eastern arborvitae is susceptible to winter stem breakage. Do not interpret every spring problem as a fertilizer shortage. ^{[3] [8]}

If none of these two plants matches the site, revisit the selection instead of forcing a winner. The Privacy Trees collection provides other forms to compare. Any substitute still needs its own climate, light, mature-size, and soil check.

Plant at the right depth

Prepare the planting area only after underground services and relevant site restrictions have been checked. Unpack promptly, keep the root ball from drying out, and inspect the plant before installation. Check root-ball moisture and keep the plants sheltered until the site is ready.

Locate the root flare, where the trunk broadens into the main roots. Do not assume that the top of the potting medium marks the correct final soil level. Make the planting hole wider than the root ball but no deeper than required to keep that flare visible at the finished grade. Backfill with the site's soil rather than creating a small pocket of unrelated rich potting mix. ^[4]

Inspect circling roots and correct the root system appropriately before planting. Keep the plant upright as soil is returned around it, then water to settle the backfill and check the final depth again. A tree that sinks after watering should not be left with its flare buried. Handle the root ball rather than hauling the tree into position by its stem. ^[4]

Apply a moderate layer of organic mulch over the root area and keep it away from the trunk. A roughly two- to three-inch layer is a practical starting thickness, not a mound piled up the bark. Leave access to check the root ball itself instead of covering every useful observation point. ^{[4] [5]}

Establish the row as individual plants

A new row is not one uniform watering unit. Check representative trees at both ends, the exposed middle, and any low area. The original root ball and surrounding soil sometimes have different moisture conditions, so investigate both rather than judging by the dry appearance of the mulch.

University of Minnesota emphasizes consistent watering during establishment and direct watering of the root zone. The exact interval changes with plant size, soil, weather, and drainage. Use regular inspections to decide when water is needed; do not repeat an irrigation timer setting through a cool rainy week and a hot windy one without checking its result. ^[5]

Make a short inspection record: tree position, root-ball moisture, nearby soil moisture, irrigation action, and any new discoloration. “Checked, still moist, no water” is a useful entry. It prevents a second person from watering merely because no water was applied that day.

Do not feed the planting to force a promised growth rate. Assess whether soil fertility actually needs correction, and follow an appropriate recommendation and product label. Light, root-zone oxygen, and available water are not replaced by fertilizer. ^[9]

Investigate browning before changing care

Older interior foliage turning brown and falling in autumn can be normal seasonal shedding, especially when the outer tips remain healthy. Browning at exposed tips, along one side, or throughout a declining plant calls for a different check. Record the pattern before trimming away the evidence. ^{[6] [7]}

Start with the site and recent events: watering changes, prolonged saturation, dry root balls, road salt, winter exposure, and physical damage. A whole row affected after the same event suggests a different investigation from one plant declining in a low spot. The pattern guides inspection; it does not establish a disease diagnosis by itself.

Severe root problems also produce weak growth and discolored foliage. Phytophthora affects arborvitae among other woody plants, but a brown tree is not automatically infected. Check drainage and roots, and use a diagnostic service when deterioration continues without a clear cause. Replanting into an unresolved wet spot repeats the original risk. ^[10]

Test the plan against two real-space examples

Consider a hypothetical side yard with a five-foot-wide planting strip between a fence and a path. The owner wants to block a ground-level seating area, not an upstairs window. An Emerald Green drawn at four feet wide leaves only one foot of total spare width in that strip. That remaining foot must accommodate all the clearance around the canopy; it is not one foot on each side.

The next step is to position the canopy outline and check access. Does the path remain usable? Can the fence be maintained? Does the row receive enough light? If those questions fail, the fact that Emerald Green is the narrower option does not make the plan viable. The usable planting strip, rather than the cultivar comparison alone, decides whether either tree belongs there.

Now consider a large rear boundary with a twenty-foot-deep planting area and a much taller unwanted view. A Green Giant drawn at eighteen feet wide fits very differently, but the spare two feet again belongs to the whole cross-section. Position the center deliberately rather than assuming that any point inside the bed reserves equal clearance on both sides.

In this second example, also check the future shade on beds in front of the row and how you will reach the back of the trees. Available ground width solves only one part of the design. A large screen can be appropriate and still be poorly positioned.

Neither example assigns a universal setback. Both use the source-based mature-width references as geometric inputs, then require a separate decision about clearance. That is the useful way to compare these plants: make the consequences visible in the space you actually have before choosing a package quantity.

Questions before ordering

Which arborvitae fits a small yard?

Emerald Green is the smaller of these two choices, but measure its full footprint and the access around it. “Small yard” does not tell you whether the planting strip is sunny, whether deer browse it, or whether ten to fifteen feet of height will solve the sightline. A narrow cultivar still belongs only where its conditions fit. ^{[2] [3]}

Can I keep Green Giant at fence height?

Do not select it on that assumption. Its reference mature scale is much larger than an ordinary garden fence. A deliberately maintained hedge is a separate design requiring a realistic pruning plan; it is not evidence that the tree has a naturally small footprint. Start with a plant whose size suits the long-term job. ^[1]

Should I plant the trees closer for instant privacy?

Closer centers create more canopy overlap, not instant mature plants. They also change the number of trees and the maintenance burden. Draw the full-width canopy first, then evaluate a maintained hedge separately. A proposed spacing only makes sense alongside those two drawings and your tolerance for early gaps.

Can I combine arborvitae with flowering shrubs?

Yes, provided each plant has enough light and room after the evergreens mature. Put the future canopy on the sketch before filling the remaining ground. For hydrangeas, the cultivar-based pruning guide also helps you avoid treating every shrub in a mixed planting as the same maintenance task.

Mark the centers before you buy

Finish three items: the view you are screening, the mature-width drawing, and the center-by-center tree count. Then write down who will inspect the root balls and how water reaches every plant during establishment. A plan that works on those four points is ready to compare with available stock. A plan that depends on shrinking a large tree later needs another drawing, not another tree.