How Much Should You Water a Green Giant Arborvitae?

Thuja (standishii x plicata) “Green Giant” is a frequent evergreen tree initially developed by the United States National Arboretum in a Danish gift tree in 1967. Its rebound was widely distributed amongst growers and landscape designers, in which it had been prized for its disease resistance and rapid development pattern. Home gardeners utilize the “Green Giant” arborvitae as a specimen tree or privacy screen, or to mark property boundaries. Proper watering and care will ensure its beauty for years.


Like other evergreens, “Green Giant” prefers moist soil conditions but doesn’t do well in soggy, standing water. Place the tree in a area of the landscape which has well-draining soil but doesn’t dry out fast. Trees planted on a hill might not get enough water consistently. Trees planted in a low-lying area of the property are subject to the wet conditions which encourage disease problems. Newly planted trees need more water than mature trees. All trees benefit from a layer of straw, chipped wood or compost mulch to hold in moisture.


Irrigate the tree 3 times per month in April through September and one or two times per month during the winter months. Young trees may dry out more rapidly than adult trees. Short periods of drought are planned, but long periods without water cause the evergreen needles to turn yellow, purple or red and lose vigor. Ongoing exposure to drought conditions triggers browning to happen at leaf suggestions, which might eventually rise to the twig. When irrigating, allow water to soak into the soil thoroughly. The tree grows from 2 to 3 feet per year when water is adequate. A mature tree reaches 60 feet in height and over 12 feet in diameter over the first 30 years of its growth.


“Green Giant” has the flattened, needle-like leaves feature of several evergreens. The branches grow in a dense, compact pattern. Its shape is tightly pyramidal to conical, with little 1/2-inch cones that adult in the autumn. Organic propagation occurs when seeds in the cones develop wings and dip into the ground, sprouting from the spring. “Green Giant” can also be easily propagated from cuttings. Hardwood cuttings are taken out of dormant, adult stems from late autumn, winter or early spring.

Site Requirements

Evergreen trees like “Green Giant” prefer to grow in full sun. Partial shade might be tolerated, but the tree gets thin and open, and it loses its characteristic form. Choose the website location to accommodate rapid development. The tree root system extends up to 2 to 4 times the height of this tree. Trees planted near driveways, sidewalks and entryways or near utility wires might become an issue within several years.

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