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How to propagate Thuja Green Giant arborvitae is easier than most people think.
You can propagate Thuja Green Giant arborvitae using stem cuttings taken during the right season.
This method gives you new trees that are genetically identical to the parent plant.
Propagating Thuja Green Giant arborvitae from cuttings saves money and lets you create a privacy hedge for free.
In this post, we’ll walk through everything you need to know about propagating Thuja Green Giant arborvitae successfully.
Let’s get started.
How to Propagate Thuja Green Giant Arborvitae from Cuttings
Propagating Thuja Green Giant arborvitae involves a few simple steps that any gardener can follow.
Here’s the process broken down.
1. Take Semi‑Hardwood Cuttings at the Right Time
The best time to propagate Thuja Green Giant arborvitae is in late summer or early fall.
Look for semi‑hardwood stems that are firm but still flexible.
Cut a 6‑ to 8‑inch segment from a healthy branch using clean, sharp pruners.
Remove the lower needles so the bottom third of the cutting is bare.
Make the cut just below a node to encourage root formation.
2. Apply Rooting Hormone for Better Success
Rooting hormone significantly improves your chances when you propagate Thuja Green Giant arborvitae.
Dip the bare end of each cutting into a powdered or gel rooting hormone.
Tap off any excess to avoid overdosing the stem.
The hormone stimulates root cell development and speeds up the rooting process.
3. Plant the Cuttings in a Well‑Draining Medium
Use a mix of perlite and peat moss or a commercial seed‑starting blend.
Fill a small pot or tray with the medium and water it so it’s moist but not soggy.
Insert each cutting about 2 inches deep into the medium.
Space them a few inches apart to allow air circulation.
Firm the medium around the base of each cutting to hold it upright.
4. Create a Humid Environment
Thuja Green Giant arborvitae cuttings need high humidity to root well.
Cover the pot with a clear plastic bag or a propagation dome.
Place the setup in bright indirect light, not direct sun.
Open the cover every few days to let fresh air in and prevent mold.
Mist the cuttings lightly if the medium feels dry.
5. Be Patient and Monitor for Roots
Roots can take 6 to 12 weeks to develop.
Gently tug on a cutting after a couple of months — resistance means roots have formed.
Once you see new growth on the top, the cutting has rooted successfully.
Transplant each rooted cutting into its own pot filled with standard potting soil.
Keep them protected for the first winter before planting them outdoors in spring.
Other Ways to Propagate Thuja Green Giant Arborvitae
Cuttings are the most reliable method, but you can also propagate Thuja Green Giant arborvitae in other ways.
1. Layering
Layering works well if you have a low‑hanging branch.
Bend a branch to the ground, wound the underside slightly, and cover it with soil.
Anchor it with a rock or wire peg.
After a year, roots will develop at the buried section.
Cut the new plant free and transplant it.
2. Seeds (Not Recommended)
You can technically propagate Thuja Green Giant arborvitae from seeds, but it’s slow and unpredictable.
Seeds need cold stratification for several weeks.
The resulting trees may not be true to the parent because they are hybrids.
For consistent results, stick with cuttings.
Tips for Success When You Propagate Thuja Green Giant Arborvitae
A few extra pointers will boost your success rate.
1. Use Sharp, Sterile Tools
Dirty or dull pruners can introduce disease and crush stems.
Clean your tools with rubbing alcohol before you start.
2. Take More Cuttings Than You Need
Not every cutting will root.
Take double the number you actually want to end up with.
3. Avoid Overwatering
Constant moisture is helpful, but standing water causes rot.
Make sure your pot has drainage holes.
4. Keep Temperatures Moderate
Aim for 65‑75°F (18‑24°C) during the rooting period.
Avoid placing the cuttings near heaters or drafty windows.
So, How Do You Propagate Thuja Green Giant Arborvitae?
You propagate Thuja Green Giant arborvitae by taking semi‑hardwood cuttings in late summer, coating them with rooting hormone, and placing them in a humid, well‑draining medium.
With patience and the right care, most cuttings will root within a few months.
Layering is another option, but seeds are less reliable for this hybrid.
Now you have everything you need to start propagating Thuja Green Giant arborvitae in your own backyard.
Happy planting.