How Far Apart to Plant Arborvitae

Spacing is where most arborvitae hedges are won or lost, and you only get one chance at it. Too wide and you wait years for the gaps to close. Too tight and the plants crowd each other, shade out their own lower branches and stay wet, which invites disease.

The rule that works for every variety: space by mature width, not by the size of the plant in the pot. A 3-foot Green Giant in a 3-gallon pot looks small. In 10 years it can be 12 feet wide or more.

Spacing chart by variety

Mature sizes are from university extension sources and nursery spec sheets. Spacing is center to center.

Sizes: Iowa State’s cultivar table, Oregon State Extension, NC State, UConn and Monrovia. Green Giant spacing: Bower & Branch and Stark Bro’s. Spacing for the less common varieties is my working figure from their published widths, using the same “roughly mature width or a bit less” rule the sources apply to Emerald Green and Green Giant.

Spacing by goal

The same plant gets spaced differently depending on what you want from it.

Formal hedge you’ll shear

Go on the tight end. For Emerald Green that’s 3 feet. You’re going to trim the sides anyway, so the plants don’t need room to reach full width. They need to touch soon.

Privacy screen you won’t shear much

Use the standard figure, close to mature width. Emerald Green at 4 feet, Green Giant at 6 to 8 feet. Bower & Branch says a Green Giant screen at 8 feet can take 2 to 5 years to fill in, which is the price of healthy, full-size plants.

“Instant” hedge

People ask for this constantly. You can plant tighter, but there’s a cost. Bower & Branch’s “instant hedge” figure for Green Giant is 5 to 6 feet, never closer, with shearing several times per season so neighbors don’t grow into each other. Below that, you’re setting up a crowded row.

Specimen or small group

Give them full room. NC State’s suggested space for individual Green Giants is 12 to 24 feet.

Windbreak or noise buffer

NC State says Green Giant can be spaced closer than specimen distance for windbreaks or noise reduction. A staggered double row (below) does this job best.

Why too close is a problem

Planting tight looks like a shortcut. Here’s what happens a few years later.

Lower branches brown out. When branch tips from neighboring plants tangle, they shade each other and die back. Walter Reeves, the Georgia gardening writer, warns that the lower limbs then turn brown, and his advice is simple: don’t let the limbs grow together. Shear the tips between plants each spring to keep a small gap.

Disease. NC State’s Henderson County office linked dense planting and shade to foliage that stays wet, cracked bark and canker. Brunswick County Extension adds that close planting in rows is a common source of later problems.

Competition. Tight plants share the same water. In a dry summer, a crowded row stresses faster.

One dies, the row has a hole. When something like root rot hits one plant, a crowded row makes it easier to spread. NC State notes that planting too many arborvitae can let diseases and insects move through.

Why too far apart is a problem

It’s less risky, just slower. Gaps take years to close, and the row looks thin in the meantime. If you plant too wide, you can fill in with a second staggered row later.

Single row vs staggered row

Single row

Every plant in a straight line at your chosen spacing. Easiest to plant, easiest to maintain, needs the least depth. This is the right choice for most yards.

Staggered (zig-zag) double row

Two rows, with plants in the second row set in the gaps of the first. Bower & Branch says this gives an almost immediate screen but needs more plants. It’s the best way to block a view quickly without packing a single row too tight.

How to lay it out: set the first row at your normal spacing. Set the second row behind it with the same spacing, shifted half a space sideways. The distance between rows should be roughly the same as the spacing within the row. For Emerald Green, Bower & Branch uses 4 feet both ways.

Staggered rows need depth. For Green Giant at 8 feet, two rows plus room to grow means a planting bed close to 20 feet deep.

Distance from fences, walls and houses

None of the extension sources I read gives a fixed setback, so here is the practical rule I’d use: put each plant’s center at least half its mature width away from anything solid, plus a foot or two of working space.

Remember you need to get behind the hedge to trim it, pull weeds and check for bagworms. Air movement matters too. A hedge jammed against a fence stays damp on that side.

Check the property line before planting. Branches that cross into a neighbor’s yard are a common source of disputes, and a Green Giant can push several feet past where you planted it.

Keep plants away from where water pools off a roof or downspout. Arborvitae hate wet roots.

How many arborvitae do I need?

Simple formula: row length ÷ spacing, then add 1 for a row that starts and ends with a plant.

The ranges allow for whether you set the end plants right at the property corners or a few feet in. If you set the first and last plants half a spacing in from each end, divide length by spacing and skip the “+1.”

For a staggered double row, roughly double these numbers.

Spacing tips at planting time

Run a string line. Two stakes, a string at the row’s front edge, and mark plant centers with flags or spray paint. A straight row looks better and is easier to maintain.

Measure center to center. Not edge of root ball to edge of root ball. This is the easiest place to lose a foot.

Buy a spare. Plants die, especially in the first year. Matching a replacement a few years later is hard. Oregon State says to buy the biggest replacement you can find so it catches up.

Dig properly. Spacing does no good if the planting is wrong. My arborvitae care guide covers depth, burlap removal and the first-year watering schedule.

Don’t run a lawn up to the trunks. Leave a mulched strip in front of the row. Mowing and trimming tight against the plants scars bark, and NC State noted that grass clippings blown into the base hold moisture against it. If you mow along the row often, a cordless string trimmer with a guard makes the edge easier, and mowing the right way keeps the discharge pointed away from the hedge.

Think about watering. A long row is easier to water with a soaker hose laid along the plants under the mulch than with a sprinkler.

Common spacing mistakes

Spacing by pot size. The tag’s mature width is the number that matters.

Green Giant at 3 feet. It’s the most common mistake I read about. Bower & Branch’s floor is 5 feet.

Emerald Green at 6 feet “to save money.” It may never close up properly. Its mature width is 3 to 4 feet.

Too close to the fence. The back of the hedge rubs, stays damp and can’t be reached.

Ignoring what’s overhead. Green Giant can reach 40 to 60 feet. Check for power lines and tree canopies before planting a tall screen.

Which variety should I plant?

If you’re still deciding, start with width. Under 5 feet of planting depth points you to Emerald Green, North Pole or another narrow type. Plenty of room and a need for real height points to Green Giant. I compare those two directly in Emerald Green vs Green Giant.

And if a row you planted tight is starting to brown at the bottom, Why is my arborvitae turning brown? covers crowding along with the other common causes.