North Pole arborvitae
Thuja occidentalis 'Art Boe'. Family Cupressaceae. Tree.
Also called Thuja occidentalis 'Art Boe', North Pole northern white cedar.
North Pole is a narrow, upright evergreen with dense green foliage, grown for screening and strong vertical accents where space is limited. It keeps its colour well in winter and needs little shaping. The species is widely grown in USDA zones 2-7, although this cultivar is usually sold for zones 3-7.
At a glance
- Sun
- Full sun to light partial shade; dense growth is best with at least six hours of direct sun.
- Water
- Moderate; keep the root zone evenly moist, especially during establishment and hot, dry weather. Avoid prolonged waterlogging.
- Soil
- Moist, well-drained loam or clay loam; tolerates chalky and alkaline soil. Poorly suited to very dry, shallow soil.
- Height
- 10-15 ft (3-4.6 m), potentially taller with age
- Spread
- 3-5 ft (0.9-1.5 m)
- Foliage
- Evergreen. Dense, flattened sprays of green, scale-like leaves; aromatic when crushed and usually retaining good green colour through winter.
- Growth
- Moderate, often about 6-12 in (15-30 cm) a year once established, depending on moisture and climate.
- Care needed
- Low
The year at a glance
- Cold hardy
- Wildlife
| J | F | M | A | M | J | J | A | S | O | N | D | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Fruit | ||||||||||||
| Plant |
Northern hemisphere months. In Australia, shift them by six.
- Difficulty
- Easy
- Toughness
- Fairly tough
Will it suit your garden?
Pick your zone, country, light and whether you have pets.
Full sun is 6 or more hours of direct sun a day, part shade 3 to 6 hours, shade under 3.
How it grows
Planting day
7 ft (2 m)
After 1 year
7 ft (2.1 m)
After 2 years
7 ft (2.2 m)
After 3 years
7 ft (2.3 m)
After 5 years
8 ft (2.4 m)
About 20 years to full size.
From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.
Good to know
- Cats and dogs
- Toxic
- Native to
- the US and Canada
- Growth rate
- Moderate
Care
Jobs through the year
- WaterApr–May, Sep–Oct, every 14 days
- Water deeply if roots are drying; check the original root ball more often for the first two years.
- WaterJun–Aug, every 7 days
- Water deeply in dry weather; skip when rainfall keeps the root zone moist.
- WaterNov
- Water deeply before the ground freezes if the soil is dry.
- MulchMar, Oct
- Top up organic mulch to 5–8 cm as needed without piling it against the trunk.
- FeedMar–Apr
- Apply a light slow-release feed only for weak growth or a confirmed deficiency.
- PruneMay–Jun
- Remove dead branches and lightly trim green tips only if needed; never cut into bare old wood.
- ProtectMar–Apr
- Pick off and destroy overwintered bagworm bags where this pest occurs.
- ProtectJun–Aug, every 14 days
- Check for mites and young bagworms; confirm pests before using locally approved controls.
- ProtectJan–Mar, Nov–Dec
- Fence against deer, shelter young trees from drying winds and gently brush off loose heavy snow.
- Water deeply during dry spells for the first two growing seasons; check the original root ball as well as the surrounding soil.
- Spread 2-3 in (5-8 cm) of organic mulch over the root zone, keeping it clear of the trunk.
- Plant with the root flare at soil level and leave enough room for the mature width.
- Apply a balanced slow-release fertiliser in spring only if growth is weak or a soil test shows a deficiency.
- Water before the ground freezes if autumn has been dry; shelter young plants from drying winds.
Pruning. Little pruning is needed. Lightly trim green shoot tips in late spring or early summer if shaping is necessary, and remove dead branches; do not cut back into bare old wood, which rarely regrows.
Through the year
- Early spring
- Check for winter browning and broken branches; wait for new growth to clarify which shoots are dead.
- Spring
- Plant while the soil is workable and moist, then water thoroughly and mulch.
- Late spring
- Lightly trim green tips if a more formal outline is wanted.
- Summer
- Check soil moisture during dry weather and inspect foliage for mites or bagworms where these occur.
- Autumn
- Remove fallen debris and renew mulch without piling it against the trunk.
- Late autumn
- Water deeply before freezing weather if the soil is dry; in mild climates, plant once summer heat has passed.
- Winter
- Gently brush off loose, heavy snow before branches bend; do not strike frozen foliage or pull off ice.
In the garden
- Plant a row along a boundary for a narrow evergreen screen, allowing space for the full mature spread.
- Use a matched pair beside a path or entrance to frame the view without frequent clipping.
- Place behind flowering perennials and ornamental grasses for a permanent green backdrop.
- Repeat individual plants through a mixed border to give rhythm and winter structure.
Garden styles it suits: Formal, Architectural minimal, Traditional, Small-space, Winter interest and Green on green.
Plant it with: Panicle hydrangea, Japanese spirea, Feather reed grass, Coral bells, Hosta and Siberian iris.
Wildlife: Dense foliage provides shelter and nesting cover for small birds. Deer readily browse arborvitae and can strip foliage beyond recovery, so protect plants where deer are common.
Problems to watch for
- Winter browning: drying winds, frozen soil and drought can scorch foliage. Keep roots watered before winter and shelter exposed young plants; assess recovery before pruning.
- Bagworms, particularly in parts of the United States: pick off and destroy the hanging bags before eggs hatch; treat young caterpillars with a locally approved control if needed.
- Spider mites: fine stippling, dull foliage and webbing can develop in dry conditions. Confirm mites by tapping foliage over white paper, then rinse foliage or use an approved treatment.
- Root rot in saturated soil: prevent standing water and correct drainage before planting. Remove severely affected plants rather than repeatedly replacing them in the same wet spot.
Safety
The foliage and concentrated oils contain thujone and other compounds that can be harmful if eaten by people, cats, dogs or horses. Chewing foliage may cause digestive upset; substantial ingestion or swallowing essential oil can cause serious poisoning. Do not use it as food or a home remedy, and seek medical or veterinary advice after significant ingestion.
Easily confused with
Emerald Green arborvitae (Thuja occidentalis 'Smaragd')
Also a narrow green arborvitae, often with brighter emerald foliage. Appearance overlaps substantially, so a reliable nursery label is more useful than foliage alone.
Degroot's Spire arborvitae (Thuja occidentalis 'Degroot's Spire')
Usually has more visibly twisted foliage sprays and a narrower, less uniformly smooth outline.
Italian cypress (Cupressus sempervirens)
Has fine, rounded rather than distinctly flattened leafy branchlets, round woody cones, and much less tolerance of severe winter cold.
The name
Arborvitae means 'tree of life', while occidentalis means 'western', referring to the species' North American origin.
Propagation. Propagate by semi-ripe cuttings in late summer or hardwood cuttings in winter; rooting can be slow. Seed will not reproduce the cultivar. North Pole is sold as a patented cultivar, so check current propagation rights in your country before taking cuttings.
Checked against open data
- Accepted botanical name
- Thuja occidentalis
- In the US and Canada
- Native in Canada and the lower 48 states.
- Native range
- Connecticut, Illinois, Indiana, Kentucky, Maine, Manitoba, Maryland, Masachusettes, Michigan, Minnesota, New Brunswick and New Hampshire.
- Measured
- Soil pH 5.2 to 7. Average height 1460 cm.
Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.
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