PLANT CARE & CHARACTERISTICS

Light Requirements: Full Sun to Partial Shade. It prefers full sun (at least 6 hours) for the densest foliage. While it can handle partial shade, it may become slightly more "open" or thin in appearance.

Water Requirements: Moderate. It likes regular watering, especially during its first two years. Once established, it is quite self-sufficient, but it prefers moist, well-drained soil rather than bone-dry earth.

Drought Resistance: Moderate. It is more drought-tolerant than most other Arborvitae varieties, but it will show stress (browning needles) during prolonged periods of extreme heat without supplemental water.

Soil Type: Adaptable. It thrives in almost any soil type—sandy, loamy, or clay—provided it is well-drained. It is also surprisingly tolerant of alkaline soils.

Deer Resistance: High. Unlike the Thuja occidentalis (Emerald Green Arborvitae), which deer treat like a buffet, 'Green Giant' is much less palatable to them. They rarely touch it once it’s established.

PEST/DISEASE RESISTANCE

POLLINATION

It is a Sterile Hybrid. The 'Green Giant' is a "triploid" hybrid—a cross between the Japanese Arborvitae (Thuja standishii) and the Western Red Cedar (Thuja plicata).

1. No Viable Seeds: While the tree will produce the small, cinnamon-colored cones mentioned earlier, the seeds inside them are almost always sterile.

2. No "Partner" Needed: Because it is sterile and not grown for fruit or offspring, you do not need to worry about planting a "male" or "female" tree, nor do you need a second variety nearby for cross-pollination.

3. Monoecious (But Non-Functional): Like its parent species, the 'Green Giant' is technically monoecious, meaning a single tree produces both male and female reproductive structures (cones).

• Male Cones: These are tiny, inconspicuous tips on the ends of the foliage that release pollen in the spring.
• Female Cones: These are the small, leathery green-to-brown cones that develop after receiving pollen.
• The Result: Even though the pollen may reach the female cones, the resulting seeds will not germinate. If you want to grow a new 'Green Giant', you cannot plant the seeds; you must take a cutting from an existing tree to create a clone.

PRUNING

1. Shaping for a Privacy Screen: To keep your 'Green Giant' lush from top to bottom, always prune it in a tapered (pyramidal) shape. The bottom of the tree should be wider than the top. This ensures that sunlight can reach the lower branches; if the top is wider, it will shade the bottom, causing the lower needles to turn brown and fall off.

2. Managing the "Leader"

• Single vs. Multi-Leader: 'Green Giants' often develop multiple vertical "leaders" (tops). For a stronger tree that won't split under heavy snow or ice, it is best to select the strongest vertical stem and prune the competing ones back slightly.
• Topping: If the tree is reaching a height you cannot maintain, you can cut the top leader. However, the tree will immediately try to send up new vertical shoots to replace it. You will need to commit to "topping" it every year or two to maintain that height.

3. Increasing Density: If your tree looks a bit "thin" or "see-through," you can lightly shear the outer 1–3 inches of the green tips in late spring. This stimulates the plant to branch out further, creating a much thicker, more opaque wall of green.

4. Sanitation: If you are pruning multiple trees in a row, and you notice any browning or "flagging" on one, sanitize your shears with 70% isopropyl alcohol or a 10% bleach solution before moving to the next tree. This prevents the spread of fungal spores like Pestalotiopsis tip blight.

PRUNING SUMMARY