Thuja Green Giant arborvitae roots best when planted in early fall or late spring, avoiding summer heat. Knowing when to plant thuja green giant is the single most important step for getting a fast-growing, healthy hedge. Get the timing right, and your trees will thrive with minimal fuss.
Planting at the wrong time stresses the tree. It might survive, but it won’t grow as quickly or as lushly. This guide covers the exact seasons, soil conditions, and steps you need to succeed.
Why Planting Time Matters For Thuja Green Giant
Thuja Green Giants are tough, but they are not invincible. Their root system is shallow and fibrous. If you plant when the ground is too cold or too hot, the roots struggle to establish.
In summer, high heat causes rapid water loss from the foliage. The roots can’t keep up. In winter, frozen ground stops root growth entirely. The tree dries out from wind exposure.
The best planting windows give the roots a chance to grow before extreme weather arrives. This is why early fall and late spring are ideal.
Fall Planting: The Top Choice
Early fall is the most forgiving season. The soil is still warm from summer, which encourages root growth. The air is cooler, so the tree loses less water through its leaves.
You want to plant at least 6 weeks before the first hard frost. This gives the roots time to anchor into the soil. In most zones, that means September to mid-October.
- Soil stays warm longer than the air.
- Cooler temps reduce transplant shock.
- Fall rains often provide natural watering.
- Roots grow until the ground freezes.
One caution: do not plant too late. If the ground freezes within a few weeks, the tree won’t establish. It may heave out of the soil during winter thaws.
Spring Planting: A Strong Second Option
Late spring is the next best time. Wait until the soil is workable and the danger of heavy frost has passed. This is usually April or May, depending on your climate.
Spring planting works well because the tree has the whole growing season ahead. The roots spread quickly in warming soil. You just need to water consistently through summer.
- Soil temperature should be above 50°F (10°C).
- Plant after the last frost date for your area.
- Be ready to water deeply if spring is dry.
- Mulch to keep soil cool and moist.
Spring-planted trees need more attention during their first summer. They have less root mass to handle heat. But with proper care, they catch up fast.
When To Plant Thuja Green Giant In Different Climates
Your local climate changes the best planting window. What works in Georgia might fail in Minnesota. Here is a breakdown by region.
Northern Zones (USDA 3-5)
In cold climates, spring is often safer than fall. The ground freezes early, sometimes by late October. Fall-planted trees may not have enough time to root.
Plant in late April or early May. The soil thaws slowly, but once it warms, growth is rapid. Avoid planting in fall unless you can do it by mid-September.
Winter protection is critical. Mulch heavily around the base. Consider a windbreak for the first winter.
Central Zones (USDA 6-7)
These zones offer the most flexibility. Both fall and spring work well. Early October is ideal for fall planting. Late March to early April works for spring.
Watch for late frosts in spring. A sudden freeze after planting can damage new growth. Cover young trees with a sheet if frost is forecast.
Summer heat is manageable. Just water deeply once a week during dry spells.
Southern Zones (USDA 8-9)
In warm climates, fall is the clear winner. Plant from October through December. The mild winter allows roots to grow all season long.
Avoid summer planting entirely. The heat is too intense. If you must plant in summer, do it on a cloudy day and water twice daily.
Spring is also possible, but you need to plant early, before the heat sets in. Aim for February or March.
Step-By-Step Planting Guide
Once you know when to plant, the next step is doing it right. Follow these steps for the best results.
1. Prepare The Site
Choose a spot with full sun to partial shade. Thuja Green Giants need at least 4-6 hours of direct sun daily. More sun means denser growth.
Test the soil drainage. Dig a hole 12 inches deep and fill it with water. If it drains within an hour, you are good. If it takes longer, amend the soil or choose a different spot.
Remove all grass and weeds within a 3-foot radius. Grass competes for water and nutrients.
2. Dig The Hole
Dig a hole twice as wide as the root ball but no deeper. The top of the root ball should sit slightly above ground level. Planting too deep is a common mistake that leads to rot.
Loosen the soil at the bottom and sides of the hole. This helps roots spread outward.
3. Place The Tree
Remove the tree from its container or burlap. If the roots are circling, gently tease them apart. Place the tree in the center of the hole.
Check that the trunk flare (where the trunk meets the roots) is visible above the soil line. Adjust the depth if needed.
4. Backfill And Water
Fill the hole with the original soil. Do not add compost or fertilizer at planting time. This can burn the roots. Water deeply as you backfill to remove air pockets.
After filling, create a small soil ring around the tree to hold water. Then water slowly until the ground is saturated.
5. Mulch
Apply 2-3 inches of organic mulch around the base. Keep it a few inches away from the trunk. Mulch keeps soil cool, retains moisture, and suppresses weeds.
Do not pile mulch against the trunk. That invites pests and rot.
6. Water Regularly
For the first month, water every 2-3 days if there is no rain. After that, water deeply once a week. Continue through the first growing season.
In fall, water until the ground freezes. In spring, resume watering when the soil thaws.
Common Planting Mistakes To Avoid
Even with perfect timing, small errors can cause problems. Here are the most common ones.
- Planting too deep: Roots need oxygen. Burying the trunk causes rot.
- Skipping the watering schedule: New trees dry out fast. Check soil moisture weekly.
- Adding fertilizer too soon: Wait until the second year. Fertilizer can damage new roots.
- Ignoring spacing: Plant 5-6 feet apart for a hedge. Closer spacing leads to crowding.
- Not hardening off: If you buy from a greenhouse, acclimate the tree to outdoor conditions over a week.
How To Care For Newly Planted Thuja Green Giants
Care after planting is just as important as the timing. Follow these guidelines for the first year.
Watering Schedule
Deep watering is better than frequent light watering. It encourages roots to grow deep into the soil. Use a soaker hose or drip irrigation for efficiency.
In hot weather, water in the morning. This reduces evaporation and gives the tree time to absorb moisture before the heat peaks.
In fall, continue watering until the ground freezes. Evergreens lose moisture through their needles all winter.
Mulching And Weed Control
Keep a 3-foot diameter of mulch around each tree. Refresh it each spring. Pull any weeds that pop through.
Weeds steal water and nutrients. They also harbor pests. A clean mulch bed solves most problems.
Pruning And Training
Thuja Green Giants need little pruning. In the first year, only remove broken or dead branches. Let the tree grow naturally.
If you want a denser hedge, pinch back the tips of new growth in early summer. This encourages branching.
Do not prune in fall. That can stimulate new growth that will be killed by frost.
Winter Protection
In cold zones, protect young trees from winter burn. Wrap them in burlap or use an anti-desiccant spray. This prevents the needles from drying out in harsh wind.
Remove any snow buildup from branches to prevent breakage. Do not use salt-based deicers near the trees.
Frequently Asked Questions
Can I plant Thuja Green Giant in summer?
It is not recommended. Summer heat stresses the tree. If you must, plant on a cool, cloudy day and water deeply every day for two weeks. Provide shade for the first month.
How far apart should I plant Thuja Green Giant for privacy?
For a dense privacy hedge, space them 5-6 feet apart. For a looser screen, space them 8-10 feet apart. They will fill in over time.
What is the best soil for Thuja Green Giant?
They prefer well-draining loamy soil with a pH between 6.0 and 8.0. They tolerate clay if drainage is good. Add organic matter if the soil is sandy or heavy clay.
How fast do Thuja Green Giants grow after planting?
They grow 3-5 feet per year once established. In the first year, growth is slower as the roots settle. By year two, you will see rapid upward growth.
Should I stake my Thuja Green Giant after planting?
Staking is not usually needed. The trunk is flexible and strong. Only stake if the tree is in a very windy spot. Remove stakes after one year.
Final Thoughts On Planting Timing
Getting the timing right for your Thuja Green Giant is simple. Early fall is best, late spring is second. Avoid summer and deep winter.
Your local climate may shift these windows slightly. Check your frost dates and soil temperature before planting. A little planning saves a lot of trouble later.
With the right season, proper planting technique, and consistent care, your Thuja Green Giants will grow into a beautiful, fast privacy screen. They are one of the easiest evergreens to establish—when you plant them at the right time.
Remember to water deeply, mulch well, and be patient during the first year. Your trees will reward you with years of lush, green growth.