Thuja Green Giant Hedge: Spacing, Growth Rate and Care

Plenty of homeowners plant a fast privacy screen, enjoy it for five years, then realize it has swallowed the side yard. A thuja green giant hedge is one of the quickest ways to get a tall, dense evergreen wall, often adding 3 to 5 feet of height a year once established. That speed is exactly why planning matters: this arborvitae cultivar can reach 30 to 40 feet tall and 10 to 15 feet wide if left alone.

For most hedges, set plants 5 to 6 feet apart center to center in a single row, keep the row at least 6 to 8 feet from foundations and 4 to 5 feet in from fences and property lines, and plan on trimming once or twice a year if you want to hold the height. Give it sun, decent drainage and steady water for the first two years and it will reward you with a screen in three to four seasons.

What Makes a Thuja Green Giant Hedge Different

Thuja Green Giant is a hybrid arborvitae selected for vigor. Compared with the more common narrow arborvitae, it grows much faster, gets considerably wider, and tends to shrug off many of the problems that plague other types. It holds its rich green color well through winter in most regions, though some bronzing is normal in very cold or exposed spots.

It adapts to a wide range of climates, from areas with cold winters to warm, humid regions, and tolerates clay as long as water does not stand around the roots. It does best in full sun to light shade. In heavy shade it grows thin and loose, which defeats the purpose of a privacy hedge.

Deer tend to browse it less than many other arborvitae, although hungry deer will sample almost anything in a hard winter. If deer pressure is high where you live, expect some nibbling on young plants.

Green Giant vs Emerald Green Arborvitae

These two get compared constantly, and the right pick depends on your space.

Choose Green Giant when you have a planting strip at least 8 to 10 feet deep and need height quickly, for instance to screen a two-story house or a busy road. Choose the narrower type when the space between your house and the lot line is tight or when you want a hedge that tops out around fence height plus a few feet. A Thuja Green Giant privacy hedge squeezed into a 4-foot strip will eventually push into the fence, the neighbor’s yard, or both.

Spacing and Setbacks

For a solid wall, plant 5 to 6 feet apart. Going down to 4 feet gives a faster fill but more competition, while 8 to 10 feet works if you are patient or want individual pyramids rather than a single hedge. For a 50-foot run at 5-foot spacing, a thuja green giant hedge needs about 10 or 11 plants.

A staggered double row, with plants 8 to 10 feet apart in each row and the rows offset, gives a deeper screen on large properties. Keep the rows about 6 to 8 feet apart.

Setbacks to plan around:

• Fences: at least 4 to 5 feet from the fence line so branches do not press against panels and you can still reach the fence for repairs. Roots are fibrous rather than aggressive, but trunks thicken and can crowd posts planted too close.
• Foundations and siding: 6 to 8 feet minimum, more if you want walking room. Branches rubbing on siding trap moisture and invite rot.
• Property lines: plant at least half the expected width inside your line, typically 5 to 7 feet. Overhanging branches can become a neighbor dispute, and many towns and HOAs regulate hedge height and placement.
• Septic, sewer and water lines: keep the hedge well off the drain field and sewer lateral. Roots seek moisture and can work into joints. Never lean over or into an open septic tank; inspections and pumping belong to a licensed septic pro.
• Power lines: because this plant can exceed 30 feet, do not put it under overhead lines.
• Driveways and corners: keep clear sight lines where the drive meets the street.

Call 811 a few business days before digging so buried utilities get marked. The service is free and protects you from hitting gas, electric and communication lines.

Tools and Materials

• Tape measure, stakes and string line
• Shovel, or a tree planting auger for long rows
• Garden fork for loosening clay hole walls
• Pruners or a utility knife for circling roots and burlap
• Mulch, roughly 2 to 3 inches deep per plant
• Soaker hose or drip line for consistent watering
• Hedge shears or a trimmer for later shaping
• Gloves and safety glasses

An auger turns a weekend job into an afternoon when you are planting a dozen or more holes. Widen each hole by hand afterward and scratch up the sides, since smooth auger walls in clay can trap roots.

How to Plant a Green Giant Hedge

1. Mark the row. After utilities are flagged, run a string line and set a stake at each planting spot.
2. Dig. Make holes two to three times as wide as the root ball and no deeper. The root flare should end up level with or slightly above the surrounding soil.
3. Check drainage. Fill one hole with water. If it has not drained within a few hours, plant slightly high on a low mound or improve drainage across the bed.
4. Loosen roots. Tease apart circling roots on container plants. On balled plants, cut away twine, the top of any wire basket and as much burlap as you can reach.
5. Backfill with native soil. Firm it gently to remove air pockets without packing it hard.
6. Water deeply. Soak slowly until the soil settles.
7. Mulch and soak again. Spread mulch in a wide band along the row, keeping it a few inches off the trunks.

Spring and fall are the best windows for planting a thuja green giant hedge in most regions. Avoid planting in the peak heat of summer unless you can water reliably.

Growth Rate and Care Through the Years

The common saying about new plantings holds true here: the first year it sleeps, the second year it creeps, the third year it leaps. Expect modest growth the first season while roots establish, then a jump in years two and three. Under good conditions, a hedge planted at 4 to 5 feet can reach 12 to 15 feet in about three to four years.

Watering: deep watering once or twice a week during dry periods for the first two growing seasons, more in sandy soil. In cold regions, give a deep soak in late fall before the ground freezes to reduce winter burn.

Feeding: most plants do fine without fertilizer. If growth is weak and foliage pale, a light spring application of a slow-release product for evergreens is plenty. Too much nitrogen produces soft growth that is prone to snow damage.

Trimming: trim lightly in late spring after the first flush and again in mid-summer if needed. Keep the base slightly wider than the top so lower branches get light. Avoid cutting back into old brown wood, which rarely regrows. Top the hedge once it reaches a few inches below your target height; it will fill out thicker after topping. Use a stable platform or hire help once the hedge is taller than you can reach safely from the ground.

Troubleshooting

Brown interior foliage in fall: normal seasonal shedding of older inner foliage. Sudden browning of outer tips points to drought, root damage or winter burn.

Yellowing or thin growth: often too much shade, poor drainage or root competition from nearby trees.

Leaning plants: usually from wind on a young plant with a small root system. Straighten and stake loosely for one season.

Split leaders after snow: brush off heavy snow promptly and trim to a single strong leader while plants are young.

Bagworms or mites: check in late spring and summer. Hand-pick bagworm cases on small plants and ask a local nursery or extension office about treatment.

Cost Ranges

Small container plants in the 1 to 3 foot range are fairly inexpensive, often from the low tens of dollars each. Plants of 4 to 6 feet typically cost from around a hundred to a couple of hundred dollars each, and larger balled specimens cost more plus delivery. Professional planting adds labor per plant. A 50-foot hedge of small plants can be done for a few hundred dollars, while an instant screen of large plants installed by a crew can run into the low thousands. Given how fast this cultivar grows, mid-size plants are usually the best value.

When to Call a Licensed Professional

Call 811 before every planting project. Hire a certified arborist or licensed landscape contractor for large balled plants, slopes, poorly drained clay, or rows near septic systems, sewer laterals or overhead lines. Leave any work near power lines to the utility or a line-clearance qualified arborist. If you plan irrigation that ties into household plumbing, use a licensed plumber or irrigation contractor and follow local permit requirements. Check with your town and HOA about hedge height limits and boundary setbacks before you plant.