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Green Giant

Thuja standishii x Thuja plicata

Compiled by · Reviewed against the 2024 Front Range Tree Recommendation List, CSU Extension & Plant Select® · Updated 2026-09-17

Green Giant (Thuja standishii x Thuja plicata) is a tree suited to the Colorado Front Range, rated "Recommended for Most Sites" on the 2024 Front Range Tree Recommendation List. It matures to about 40–60 ft tall and 12–18 ft wide, needs medium to high water, and prefers full sun to partial shade. Needs protected area.

Site fitRecommended for Most Sites
medium to high water40–60 ft tall and 12–18 ft wideDeer-resistant

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At a glance

Will it survive here?

Hardiness zones
USDA 2–8
Water needs
medium to high water
Sun
Best in full sun; tolerates partial shade.
Soil
clay, loam
Soil pH
6.0–8.2
Hail tolerance
high
Wind tolerance
high
Salt tolerance
moderate

How big, what shape?

Mature size
40–60 ft tall and 12–18 ft wide
Mature form
Pyramidal
Spacing / clearance
~18 ft of clearance
Growth rate
Moderate
Lifespan
Long-lived

What it looks like, and when

Foliage
Evergreen

Who else benefits

Pollinator value
low
Deer
Generally deer-resistant
Colorado native
No

Site factors to consider

  • Watch: Leaf ScorchIts leaf edges brown in hot, dry wind, so give it steady summer water and some shelter from the worst afternoon blast.

Frequently asked questions

Is Green Giant good for the Colorado Front Range?
Yes, Green Giant is a well-suited tree for Colorado's Front Range, rated "Recommended for Most Sites" on the 2024 Front Range Tree Recommendation List.
How big does Green Giant get?
It matures to about 40–60 ft tall and 12–18 ft wide.
How much room does Green Giant need?
Give Green Giant about 18 ft of clearance from buildings, fences, and other trees so the mature canopy isn't crowded.
What shape does Green Giant grow into?
Green Giant typically grows into a pyramidal, conical outline that is widest at the base. This is the species' usual mature form, named cultivars (columnar, weeping, or compact selections) can differ, so check the specific cultivar.
Is Green Giant hardy on the Front Range?
Green Giant is hardy in USDA 2–8. The Colorado Front Range spans roughly USDA 4b–6a, so it is well within range.
How much water does Green Giant need?
It needs medium to high water once established.
How fast does Green Giant grow?
Green Giant is a moderate-growing tree. Growth rate depends on water and site conditions on the Front Range.
How long does Green Giant live?
Green Giant is long-lived, a multi-generational tree given good siting and care. Actual lifespan varies with site, water, and care.
Is Green Giant native to Colorado?
No. It is not a Colorado native, but it grows well on the Front Range.
Is Green Giant deer-resistant?
Green Giant is generally considered deer-resistant, though no plant is deer-proof when browse pressure is high.

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Related trees

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