Thuja × soeegaardii
'Green Giant' arborvitae
Garden hybrid; parent species native to Japan and western North America
Overview
Thuja x soeegaardii, grown as the cultivar 'Green Giant', is a hybrid of T. standishii and T. plicata forming a large evergreen conifer. It grows upright in a dense, narrow pyramid 30-60 feet (9-18 m) tall and 8-20 feet (2.4-6 m) wide, with a single straight leader and branches held nearly to the ground. The foliage consists of flattened sprays of scale-like leaves, glossy mid- to dark green through summer and often bronzing slightly in cold winter wind. Growth is rapid in youth, with vertical gains of 3-5 feet (0.9-1.5 m) per year on young plants in good conditions, slowing as the tree matures. Small woody cones about 0.5 inch (1.3 cm) long form on older growth but remain sparse. The crushed foliage is aromatic. The dense habit casts heavy shade and needs considerable width at maturity, so it outgrows narrow spaces. Foliage contains thujone and can cause stomach upset in pets if eaten.
Native Range
A hybrid of garden origin rather than a wild plant. Its parent species are the Japanese T. standishii and the western North American T. plicata, which do not overlap in the wild. The hybrid is grown widely across temperate North America and Europe for screening.Suggested Uses
Planted as a fast screen or windbreak, spaced 5-6 feet (1.5-1.8 m) apart in a row, and as a single specimen where there is room for a 30-60 foot (9-18 m) tree. Used in larger gardens, along property boundaries, and in rural shelterbelts in zones 5-8. The mature size makes it unsuited to small urban lots or planting close to buildings.How to Identify
Appearance
Size & Dimensions
Height30' - 60'
Width/Spread8' - 20'
Reaches mature size in approximately 10 years
Colors
Foliage Colors
Fall Foliage Colors
Bloom Information
As a conifer it does not flower. Pollen cones and small seed cones develop on mature branches in spring, with the woody seed cones ripening by autumn to about 0.5 inch (1.3 cm). Cones are sparse, and the plant is grown for foliage rather than for any flowering display.
Detailed Descriptions
Foliage Description
dark greenGrowing Conditions
Sun Requirements
Requires 6-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Set plants in full sun to light shade in moist, well-drained soil; growth is densest and fastest in full sun. Water deeply each week for the first one to two seasons until the root system establishes, after which the tree tolerates short dry periods but browns at the tips during prolonged drought. It grows in loam, clay, and sandy soils across a pH of 5.5-7.5. Spacing of 5-6 feet (1.5-1.8 m) forms a solid screen, while wider spacing lets each tree develop its full pyramidal form. Bagworms and occasional foliage blight occur, and heavy wet snow or ice can splay multi-stemmed plants. Deer browse it less than T. occidentalis.Pruning
Little pruning is required for screening, as the natural form is dense and even. Trim the sides in late spring or summer to hold a hedge to a set width, cutting only into green foliage since old bare wood does not resprout. A single leader is kept by removing any competing upright stems while the tree is young.Pruning Schedule
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late springsummer