Emerald Green vs Green Giant Arborvitae

These two get sold side by side at every garden center, often with the same tag line about “fast privacy.” They’re very different plants. One is a hedge. The other is a tree that happens to make a good screen.

The mistake I see people describe most often on homeowner forums is buying Green Giant for a narrow side yard because it’s fast, then fighting it for years. The opposite mistake is lining a long, open property line with Emerald Green in deer country and watching the bottom 4 feet get eaten each winter.

All facts below come from university extension sources and nursery spec sheets. Where they disagree, I give the range.

Quick comparison

Sources: Oregon State Extension, NC State Extension Plant Toolbox, Purdue Arboretum, Iowa State, UConn, Michigan State and Oregon State’s plant disease handbook.

Where each one comes from

Emerald Green is a selection of the eastern arborvitae, a tree native to northeastern North America and Canada. It was introduced from Denmark, and in Europe it’s sold under its original name, ‘Smaragd’ (Danish for emerald). It’s the most common hedge arborvitae in the US. Oregon State calls it the most common hedge in the Pacific Northwest.

Green Giant is a hybrid of western redcedar (Thuja plicata) and Japanese arborvitae (Thuja standishii). According to NC State, it was developed in Denmark in the 1930s and came to the US in 1967 through the U.S. National Arboretum. It got popular in the South as a replacement for Leyland cypress.

That parentage explains most of the differences. Green Giant inherits size and vigor from western redcedar, a big forest tree. Emerald Green is a compact form of a cold-climate species.

Size: the deciding factor

This is the one that matters most, and the one people underestimate.

Emerald Green reaches about 12 to 15 feet tall and 3 to 4 feet wide, according to Oregon State and Iowa State. Purdue lists 10 to 15 feet. NC State’s Henderson County office says it typically reaches about 20 feet tall and 6 feet wide in North Carolina, so warmer climates with long seasons can push it bigger. Expect a narrow column that fits along a driveway or fence.

Green Giant reaches 40 to 60 feet tall and 12 to 18 feet wide (NC State and Oregon State). Nursery tags often say 30 to 40 feet, but the extension numbers are higher, and NC State warns it can quickly outgrow spaces that are too small.

Picture that width. A Green Giant planted 3 feet from a fence will eventually push 6 to 9 feet past it. Planted next to a house, it’ll scrape siding and gutters.

Growth rate

Green Giant is the fast one. NC State says up to 3 to 4 feet per year in good conditions, and the JC Raulston Arboretum in Raleigh recorded 2 to 4 feet a year. UConn gives 3 to 4 feet per year once established. That’s the “established” part that nursery ads skip: the first year or two in the ground are mostly root growth.

Emerald Green grows more slowly. Nature Hills and Bower & Branch both put it at about 1 to 2 feet per year.

So if you plant 4-foot plants of each, after five good years you might have a Green Giant well past 15 feet and an Emerald Green closer to 8 to 10 feet. Those are estimates from the growth rates, not guarantees; soil, water and sun swing them a lot.

Hardiness zones

Emerald Green handles cold much better. Purdue and Briggs Nursery list it as hardy to zone 3, and UConn lists the species for zones 2 to 7. Purdue also describes it as very heat tolerant.

Green Giant is listed for zones 5a through 8b by NC State. Some nurseries list zones 5 to 7 only.

In practice: in zones 3 and 4 (northern Minnesota, North Dakota, much of Maine and Vermont), Emerald Green is the safe choice. In zones 7 and 8 across the Southeast, Green Giant is the one extension offices in NC State’s network talk about.

Spacing

Spacing follows width.

Emerald Green: Oregon State suggests 3 to 4 feet apart for a hedge. Bower & Branch uses 4 feet as its standard.

Green Giant: Stark Bro’s suggests 5 to 6 feet for a compact privacy hedge. Bower & Branch uses 6 to 8 feet as standard and says never closer than 5 feet. NC State gives 12 to 24 feet for individual trees, closer for windbreaks.

Plant Green Giants at 3 feet because “they’re fast” and you’ll have a crowded wall where branches fight, inner foliage dies and the lower limbs brown out. Gardening writer Walter Reeves makes this point: don’t let neighboring limbs grow together.

I break this down by variety and goal in How far apart to plant arborvitae, including staggered rows and how many plants you need.

Deer

This is the clearest win for Green Giant.

Emerald Green is a selection of a deer favorite. UConn lists eastern arborvitae as a favorite deer food, and Purdue notes deer may feed on Emerald Green. Oregon State says deer usually browse the bottom 4 to 5 feet. Some nursery pages call Emerald Green “deer resistant,” but the extension sources don’t back that up.

Green Giant is listed as deer resistant by NC State, and UConn says it’s seldom browsed. No plant is deer-proof when deer are hungry enough, and Nature Hills says as much on its own page. Still, the difference is real.

If deer walk through your yard every winter, Green Giant is the safer bet. If you love Emerald Green’s size, plan on fencing or wrapping. Oregon State says fencing is more reliable than repellents.

Snow and ice

Both can break.

Michigan State lists ‘Green Giant’ and ‘Emerald Green’ together among columnar arborvitae that don’t handle heavy snow or ice well. UConn notes heavy snow often damages eastern arborvitae. Some nurseries advertise Green Giant as resisting heavy snow, but the extension guidance is to protect both.

The protection is the same for both: tie or wrap them about two-thirds of the way up in late fall with soft cloth or burlap, and take it off in spring. Oregon State says freezing rain does more damage than snow, so ice storms are the real threat.

Emerald Green’s narrow column is easy to wrap. A mature Green Giant is too big to wrap at all, so with those you’re mostly relying on the tree’s own strength and brushing off what you can reach.

Winter color

Emerald Green keeps its bright green through winter. Purdue, Briggs and Oregon State all note this, and it’s one of the main reasons it’s popular in the North. The plain species tends to go yellow-brown in winter.

Green Giant shows some bronzing in winter, according to NC State’s Extension Gardener newsletter. It greens up again in spring.

Sun, soil and drainage

Both want sun. NC State says Green Giant does best in full sun with light afternoon shade and tolerates partial shade. Purdue lists Emerald Green for full sun to partial shade. In real shade, both thin out.

Both tolerate a wide range of soil pH. NC State lists Green Giant on clay, loam, sand and rocky soils.

Drainage is where they differ on paper. Oregon State’s plant disease handbook rated ‘Smaragd’ as the most susceptible of the arborvitae it compared to root rot, with western redcedar (Green Giant’s parent) the most resistant. NC State still lists root rot in poorly drained soil as a Green Giant problem, so neither belongs in a wet spot.

Green Giant has another weak point: NC State says it doesn’t tolerate salty soils or salt spray. Keep it away from salted roads.

Pests

Both get bagworms. NC State lists bagworms as an occasional Green Giant pest, and Purdue lists them as a problem for Emerald Green. Spider mites hit both too, especially in heat on south- and west-facing sides.

Otherwise Green Giant has a cleaner reputation. NC State says it resists most diseases and insects.

What to do about browning from either one is covered in Why is my arborvitae turning brown?.

Lifespan

NC State lists Green Giant at 40 to 60 years. I couldn’t find a published lifespan for Emerald Green from an extension source, so I’ll leave that one alone.

Maintenance

Emerald Green stays narrow by itself. Most owners do little more than a light trim of new growth in spring.

Green Giant needs little pruning to hold its shape, according to NC State. The work comes if you try to keep it smaller than it wants to be. You can trim the sides of young plants to make a hedge, but holding a 50-foot tree at 12 feet means shearing two or three times a year, forever. Bower & Branch says as much for tight “instant hedge” spacing.

Both share the same rule: arborvitae won’t regrow from bare stems, so cut only into green growth. More in my arborvitae care guide.

Who should plant which?

Can you mix them?

Yes, and it can work well on a long property line. Some people plant a back row of Green Giant for height and a front row of Emerald Green or another narrow variety for density lower down. You need real depth for that: Green Giant’s 12 to 18 foot spread plus a row of 3 to 4 foot Emerald Green means planning for 15 feet or more from the property line to the front of the bed.

If you’re designing a smaller yard, see my small garden design ideas before committing to anything tall.

My verdict

For most suburban lots, Emerald Green is the right arborvitae. It’s narrow, cold hardy, keeps its color and stays at hedge height without a fight. Its weak spots are slow growth, deer and wet soil.

Green Giant is the better choice when you have the space and want a tall screen fast, or when deer clean out everything else. Just measure first. A plant that ends up 12 to 18 feet wide doesn’t belong 3 feet from a fence.