Green Giants Arborvitae

Green Giants: Planting, Care, and Maintenance Guide 

Green Giants are built to grow fast and stay full, but a few smart choices early on set them up for long-term success. From planting and watering to pruning and seasonal care, the basics below help your trees establish strong roots and maintain a dense, healthy screen as they mature.

Planting Location and Soil

Green Giants grow best in full sun but handle partial sun as well, as long as they receive at least five to six hours of direct light each day. They adapt to many soil types, including clay or poorer soils, but prefer moist, fertile, well-draining loam. Avoid planting in areas with standing water, poor drainage, or salty soil conditions.

Spacing

For a privacy screen or hedge, space trees about 5 feet apart (center-to-center). Planting too close may cause competition for water and nutrients as the trees mature.

Planting Depth

Dig a hole twice as wide as the root ball and the same depth. The top of the root ball should sit level with the surrounding soil.

Watering

Proper watering is critical during the first year.

• First year: Water regularly to keep soil evenly moist, not soggy. Avoid standing water and focus on soaking the root zone, not the foliage.
• After establishment (around one year): Reduce watering to roughly one inch every 7–10 days. Increase watering during hot summers or drought.

Tip: Deep, infrequent watering encourages stronger root development.

Mulching

Apply a 3–6 inch layer of mulch around the base of the tree to help retain moisture and regulate soil temperature. Keep mulch a few inches away from the trunk to prevent rot, pests, and growth issues.

Fertilizing

• At planting: Do not fertilize newly planted Green Giants. If desired, mix compost or organic matter into the soil instead.
• Second year onward: Fertilize in early spring before new growth begins. A light feeding in early fall is acceptable, but avoid late fall fertilization.
• Fertilizer type: Use a balanced, slow-release fertilizer such as 10-10-10 to support overall health, root development, and foliage growth.

Common Pests and Diseases

Green Giants are generally resistant, but occasionally watch for:

• Scale insects
• Bagworms
• Root rot, usually caused by poor drainage

Pruning and Maintenance

Pruning is not required, as Green Giants naturally grow tall and uniform. However, light pruning can be useful.

Pruning helps with:

• Shape and size control, especially for hedges
• Denser growth and fuller foliage
• Preventing overgrowth in smaller spaces
• Removing dead or damaged branches for overall health

Topping Green Giant Arborvitae

To limit height, the central leader must be pruned. Here are the steps to control vertical growth:

Step #1 Timing: Prune in late winter or early spring, while the tree is dormant. Avoid late fall pruning.

Step #2 Locate the leader: Identify the topmost vertical shoot.

Step #3 Make the cut: Use clean, sharp tools and cut just above a lateral branch or bud.

Step #4 Shape the top: Lightly trim surrounding branches so the tree maintains a natural, tapered look.

How to Prune

Tools: Use sharp pruning shears, hedge trimmers, or loppers based on branch thickness.

General guidelines:

• Focus on shaping rather than heavy cutting
• Remove no more than one-third of total growth in a single session
• Make clean cuts above healthy lateral branches

For bushier growth: Prune the central leader to encourage outward growth.

For hedge-style planting: Trim tops and sides evenly. Keep the base slightly wider than the top so sunlight reaches the lower branches.

When to Prune

• Late winter to early spring: Best time for most pruning
• Mid-summer: Light trimming to maintain shape
• Avoid late fall: New growth may not harden before winter

Special Pruning Tips

• Establish one strong central leader on young trees
• Avoid cutting into old, woody sections with no foliage
• For hedges, trim twice a year: early spring and mid-summer

Pruning Neglected Green Giants

If a tree has grown too large:

• Reduce height gradually over several years
• Thin interior branches to improve airflow and light penetration

Winter Protection

• Snow and ice: Gently brush off heavy buildup
• Wind and cold: Use burlap wraps in exposed areas
• Mulching: Refresh mulch in late fall to insulate roots

General Maintenance Tips

• Check soil moisture during hot or dry periods
• Refresh mulch yearly
• Watch for yellowing foliage, which may indicate drainage or nutrient issues
• Remove weeds and competing plants near the base

With proper care, Green Giant Arborvitae stay healthy, manageable, and dense, providing long-lasting privacy year after year.