Thuja standishii x plicata 'Green Giant' / Green Giant hybrid arborvitae

Thuja standishii × plicata 'Green Giant' is a very fast growing selection of hybrid arborvitae. It forms a narrowly conical to pyramidal tree with sprays of rather open foliage, rich glossy green above, paler green below. Typical rate of growth in most areas is up to 5 feet (1.6 m) per year, resulting in a large tree 50 feet (15 m) tall by 5 feet (2 m) wide after 10 years in the landscape.

D.T. Poulsen nursery of Copenhagen, Denmark, selected and introduced this cultivar in the mid-1960s. It is marketed as a very effective tree for screening and is regarded as a hardier substitute for Leyland cypress (Cupressus × leylandii), particularly in North America.

Attribution from: Aris Auders and Derek Spicer, RHS Encyclopedia of Conifers, Kingsblue Press ©2012

Thuja plicata x standishii 'Green Giant' — a spacing illustration, on the grounds of The US National Arboretum, Washington, D.C., during the first week of May, 2006;
Photo by Dax Herbst
Thuja plicata x standishii 'Green Giant' —at the Gotelli Collection, US National Arboretum, Washington, D.C.
Photo by Dax Herbst

Comments

Richard van Iderstine

What is the life span? Thanks, Rich

Mary Mies

What is the life span. Thanks , Mary

David Olszyk

Hi Mary, since this hybrid has been around only since the 1960s and the original plants are still with us, we can positively say 60 years. However, since the parent species are known to live for 3-400 years, so there's no reason to believe that the hybrid won't be long-lived as well.

Jan Anderson

Can you give me some idea of how difficult it would be to keep 1-2 ft thuja green giant arborvitaes alive to be big enough to plant in a permanent location.
1. would it be better to pot them and keep them in a green house or plant them in the ground where they are going to stay.
2. are there tips or tricks to keeping them alive and growing fast? fertilizers etc
3. any idea how big these plants will actually be with about 2 years growth?

David Olszyk

Hi Jan,

If your plants are in pots, and watered when needed, they'll do fine. Greenhouse is 100% not needed. How big are they now?

Slow-release fertilizer like Osmocote would help your cause. DO NOT PLANT IN MIRACLE GROW SOIL!!! Best to create your own planting medium from a combination of fine bark, pumice, and a little compost.

Once established, your plants may be up to 4.5 feet tall after 2 years.

Ray Crawford

Is the green giant suited for poorly drained clay soils?

David Olszyk

Taxodium and Ch. tyoides are better suited, but 'Green Giant' would work ok. It would help your cause to build berms out of mineral-rich, well drained soil to keep roots from rotting.

JoAnn Polakoff

Is the Green Giant a deer resistant tree? Does it grow well in partial shade? How old is a 4-5 foot tree?
Are these trees expensive compared to other comparable trees?

David Olszyk

Hi JoAnn

1. If deer are overpopulating your area, they will eat anything green. 'Green Giant' is no more or less deer-resistant than any other tree.

2. It doesn't grow well in part shade. It'll grow slower and less dense.

3. The American Conifer Society has no way of knowing how much one plant costs in comparison with others.

Michelle

Hello,

We just bought nine 6.08 gallon green giants from Lowes yesterday, 04/18/20. The recommended spacing on the tag is 15 feet, while other websites suggest planting as close as 5 feet. How close should we plant these trees? We want to create privacy from neighbors and block the view a bit. We don't want a solid hedge. How can the planting distance vary so much, as well as the height and diameter. Our tag shows 30 feet as mature height and 20 feet as mature width. Thanks for your input!

David Olszyk

if you plant them 15 feet on center, the plants will be touching in about 15 years. Size on tag varies because a lot of people will shear and otherwise mess with the plants. It all comes down to the fact that these trees will grow at a steady rate for 50-300 years and will vary based on climate, care and soil chemistry. Growth rates will always vary pretty wildly and is by no means exact science.

Michelle

Thanks David! We decided 8 feet apart staggered in two rows 6 feet apart. Will that be okay? Thanks!

David Olszyk

that'll give you a solid wall in 8 to 10 years.

Michelle

Thanks again, David! I appreciate your quick responses. :)

Raphael Rezende

Hi David. We bought a few of these from grower in South Carolina (Thuja Gardens) that guarantees his trees will not grow more than 25-30 ft and 8 ft wide. We managed to find Thujas green giants at a local home depot and are considering creating hedge on other section of property however the height and width varies significantly (up to 12 wide and 60 ft tall at maturity). How can one species vary so much? are the larger trees possibly hybrids of Leyland Cypress which we want to stay clear of?

David Olszyk

Hi Raphael ... the reason for all of the different claims of mature height is a simple one. Growers and retailers are free to put whatever they please on plant tags. There are no laws or regulations for this.

That grower is SC is a brilliant example. His claim is spectacularly false. No tree will grow to a certain height then stop unless it's dead. These plants grow at a predictable rate for many decades if not centuries.

In the case of 'Green Giant' ... your plants will reach heights of 25-30 feet after 5 to 7 years ... then keep going: 50-60 feet after 10-15 years, then 100-120 feet after 20-30 years. Just do the math!

JoAnn Polakoff

What is the best conifer to plant for privacy in a semi shaded area. I need a fast growing tree, one that stays full at its base.

Rod

I bought a home recently in Northern VA where the owners planted Leyland Cypress trees all around the border of the property about 8 feet apart 20 years ago.... probably 75 of them in total and they got super tall but all of them are either dead or well on their way. Less than 25% of them remain and those left are dying from the bottom up. I've had several landscapers and an arborist come by and hey all say it's not disease, but just that they are terrible trees and will die like I'm seeing when they are planted too close. They are all recommending Green Giants to take the place of the Leyland's but this is a BIG expensive decision as you can imagine... any hesitation to Green Giants being a good solution as a fast growing privacy fence? The deep soil is poorly draining clay, but they have put very good rich topsoil all throughout the property and everything else is thriving. There are a good number of large deciduous trees as well, so some areas will get bright sun while others will be fairly shaded especially during summer until the Green Giants grow more. We are looking for 10-12 foot Green Giants to plant, and it'd going to cost about $75k for all the removal and replanting so I don't want to make a bad decision here! :-). Any help / suggestions is most appreciated.

Vivian LaBarre

Hi I am in North Georgia and getting ready to plant 4 of the Thaja standishii x plicata. Georgia soil is hard and clay like. What amendments should I use in the area and what ratio of fertilizer. Part shade to afternoon and then full sun. Need for privacy and hopefully some noise control. I think they are beautiful. Any help you can give me I would greatly appreciate.

David Olszyk

never fertilize a landscape unless a soil test indicates deficiency!! Remember this forever! If you're in impossible clay, you'll have to loosen up the ground and berm it up with porous substrate. Pit-run from a quarry works great. Conifers in nature often grow out of solid rock.

Diane

We bought and planted 5 arborvitae last June, one tree started to turn brown in April, now all five have brown areas on them, we live in Northern Michigan, all of our perennial gardens are fine, no pests or disease.. Can you diagnose what this could be? We removed half of the tree that started browning first. We worry we will have to replace them all.

David Olszyk

Hi Diane, your question brings up many more questions.

Since you planted in early summer last year, did you keep up on irrigation for the remainder of the hot season? Fall is the time to plant trees, especially if they're already large.

Were your plants in pots? ... or B&B? How large were they? If B&B, did you cut the wires / strings holding the root balls together?

Did you expose the root flare before planting? The #1 cause of sudden conifer demise is planting them too deeply.

Lisa

I planted mine about 10 + years ago. About 5 years in they were very yellow, it lasted about 2 seasons, I thought they were dying.. they have fully recovered from that and are a healthy beautiful green. I absolutely love them and wish I had planted more. The bigger they get the prettier they are.

CharlieT

I have two offset rows of Green Giant arborvitaes, 9ft apart in all directions. They were slow to start, but now two years later seem to be taking off growing in all directions. However, all of a sudden I have one that is browning quite a bit and some that are browning from the inside of a branch working it's way towards the tips of the branch, here and there. I've checked for mites, insects, nothing. I use a rain gauge and would like to know, what is a good weekly inch rain fall amount of watering?
Should I let the soil dry out between watering?
What is a good liquid fertilizer to use, brand, combination X-X-X?
Thank you, Charlie.

David Olszyk

never fertilize a landscape unless a soil test indicates deficiency!! Remember this forever!

If your getting an inch of rain weekly, additional irrigation is not necessary.

Did you plant too deeply? Can you see the root flare of each plant? If the root flare is buried, your plants will die within 5 to 15 years.

CharlieT

Thank you David for replying.
The trees were planted at same level as they were in the original large containers. Not deeper, not higher. The roots were given room as "Crocket's Victory Garden" used to say, "quarter hole for nickel plant".
I haven't had soil tested, pending.
I added a wood chips mulch and I can see the very small "runner type" roots spreading out under the layer of mulch. I started with 10 trees, all doing well, growing well. The one in question I noticed has vertical cracks in the main trunk, here and there. All others, no problems. Again, thank you for taking the time to help.

David Olszyk

Charlie, saying that you planted them at the same level could still be a huge problem. I've seen root flares buryed inches too deep in the pot. B&B product is often worse. Unfortunately, we can't always count on nurseries to do this right.

Dave S.

Can I keep these potted forever to limit growth?

David Olszyk

Forever is a very long time ... While I've never seen anybody apply bonsai techniques to 'Green Giant', I see know reason why it wouldn't work. Given how much of a robust grower this one is, you're going to need to root-prune and repot on a yearly basis, then be equally aggressive with pruning the top-growth.

Nate

You answered someone's question with the importance of not using Miracle Grow soil. Unfortunately, we planted several plants of native soil mixed with Miracle Grow potting soil. Do you think we should start over, or try to remedy our mistake somehow?

David Olszyk

that's a hard one. The soluble salts that comprise the fertilizer part will have been washed away after a few waterings. The burned roots will probably recover. I would only recommend getting rid of the bad soil amendment part if it makes the soil mix exceptionally swampy. Most conifers need mineral-rich, fast-draining soil.

I use miracle-grow soil for potted annuals and heavy feeding aroids like Amorphallus konjac. That stuff is totally inappropriate for all woody plants.

Eli Morton

Are thuja standishii x plicatas susceptible to bagworms? We have serious problems with them in central Indiana.

Michelle.Anderson

Hello!

We are considering planting a hedge of Green Giants on one side of a to-be-planted orchard to help block pesticide/herbicide drift from neighboring property. We need to go just a single row and have read that planting 5 feet on center will generally work for our application. Is that accurate? Also, I am trying to determine just how wide I should expect Green Giants to get at maturity when they are grown as a hedge. I would prefer to not trim.

Much thanks!

-Michelle

Paul Bishop

We planted a row of the Green Giants in 2005. They are exposed to full sun most of the day. For the first 10 years we watered them with a drip hose. We stopped the drip watering after they go to over 20 feet. They are now roughly 40-45 foot tall. They do get quite wide at the base. They tolerate heavy wet snow with no issue!! We also stopped root feeding them at the 20 foot mark. They are still growing!! No brown spots. The base of the tree is full and they just dance with the wind. And more birds use they than I could possibly count.

Scott

I live in central California where the temps reach 100 degrees routinely in the summer (zone 9b). I have seen some websites that say the Thuja will do fine in zones 5-9. Others limit it to zones 5-8. I plan on making a hedge with these using drip irrigation. Will the dry heat of the summer be a problem for Thuja Green Giant?

Jo Kelley

I would like to use the 'Green Giant' as a screen for property that we will be building a home on in about 2 years. Can I buy seedlings now & plant them in pots now to get a jump start on growth. We will be in USDA zone 7b. We will have 1.77 acres so I will need many plants. Hoping to avoid high expense by starting seedlings now. Ideas?

David Olszyk

sure. Just make sure you use the proper-sized pot and appropriate growing medium for your plants. Miracle-gro products are fine for grass and petunias but completely inappropriate for conifers.

Pat aRice

I have 5 Thuja plicata going on 2nd year we are in a severe drought in Massachusetts; afraid to lose. They are ?6’ tall look great BUT browning leaves on lower branches, water ban can’t water help.

David Olszyk

are you asking about Thuja plicata (western red-cedar) or Thuja × 'Green Giant' ??? Two different conifers with different requirements.

Ronald Schlak

WATER AT NIGHT ?
cultivate around them so any rain they do receive , soaks in

Lisa Bryant

Hi there, I am based in NZ and need about 300 green giants for a hedge/shelter around our 1 acre property. Unfortunately we only have one supplier in NZ who is not the most helpful or customer focused. Do you know if we wanted to import them who we could contact? We have done a lot of research on the best hedging/shelter for our area and these come up with top marks.

David Olszyk

Hello Lisa, the American Conifer Society is a non-profit organization that is dedicated to conservation and education. We have no retail presence and definitely no capacity for shipping hedging material internationally.

Jesse

In the picture you have showing spacing, do you know where that is and more importantly, what the spacing is?

I planted 2 rows 5 feet apart and 8 feet on center in each row. That's 6.5 foot diagonals. I'm looking for something that does one day grow together up to 25+ feet but doesn't kill the plants decades to come.

It is zone 5b and open to the wind so imagine these factors might slow height but would think one day they could still be 60 feet.

If so, even 15 feet at the base is pretty narrow.

Heck, even the 8 foot centers are a bit close at that point... let alone the 6.5 feet between diagonals.

I like the look of the spacing picture since that narrowness looks like and can see them grow together yet pretty high up at some point without completely overcrowding.

My plants have been in ground for a year but i could maybe move them. What would you suggest? Or should I just not spend effort and stress the root systems and leave them be?

David Olszyk

Hi Jesse ... the photo caption says that the photo was taken in the National Arboretum in 2006.

Always be aware that woody plants like this never stop growing. Wanting a good screen after 10 years will likely look like a hot mess after 50 years, unless you do some thinning at some point. With this one, width will generally be 20% of height. Just do that math: if it grows 5 feet a year, it'll also get 1 foot wider every year.

Don Rollo

I live on a lake with a slight slope to the water,when digging we will hit water about 5 foot deep, will the Thuja 'Green Giant' survive here? It is mostly sandy soil.We just removed a Maple tree which had the roots on top of the ground. We are using the trees for a privacy wall .

David Olszyk

no way of knowing ... you didn't say where on Earth your lake with a slope is.

Terri

Hi David,

We have sixty Green Giant Thujas in our yard. We planted them around three years ago. They've been doing well, but last summer ONE of them died. Now we are noticing that they are all "browning" but yet I can see new growth on them.
We had the soil tested and the result was as follows:

The pH value of this soil is moderately acid in reaction and is a satisfactory range. The low electrical conductivity reading indicates the levels of soluble salt are low.
The fertility analysis shows low nitrogen, phosphorus, potassium calcium and magnesium. The concentrations of all other nutrients are in satisfactory to high ranges.
The sodium and chloride levels are low and will not cause toxicity problems. The low ESP value indicates that the sodium that is present will not create a hazard to the soil structure.
As we discussed, the low fertility may be contributing to the possible stem blight on these trees and an application of the following fertilizer materials per 1000 sq ft is recommended:
Gypsum 25.0 lbs
6-24-24 Mixed Fertilizer 20.0 lbs
The above materials should be watered in thoroughly after being applied.

Should we wait until Spring or should we do this now so we don't lose any more trees?
Thank you.

David Olszyk

for fertilizer to have any effect on plants, the plant needs to be actively growing. If that's the case with your plants, then by all means apply the product. If the plants are dormant, the fertilizer (and your money) will be washed away by rain. It's the nature of soluble salts.

Pat Morton

We planted arborvitae in late October, zone 7a. There were in 8 gal. pots and were about 4/5 feet tall. We planted according to directions. One of the trees started turning a brownish tan from the bottom shortly after planting. It kept getting brown/tan until all of it is now that color. The others on either side of it seem to be doing fine. Should I give up on this tree and replace it? Is there any particular fertilize we should use? When is the best time to apply it? Thank you, pat

David Olszyk

Hi Pat, some bronzing in the winter is normal in Cupressaceae. If spring comes and the tree does not return to green, it's probably dead. Death in conifers can sometimes take up to three years.

Fertilizer: never fertilize anything in the landscape unless a professional soil test indicates a deficiency. Since you say that the majority of your install is healthy, that's probably not the case with this individual plant.

If you still wish to fertilize, doing so does absolutely nothing if the plant is dormant. It'll just wash away into the aquifers with snow and rain.

Pat Morton

Thank you, David. I will heed your advice about fertilizer. The tree I mentioned died and 3 others show some browning. I transplanted the three to another area and replaced them with much healthier trees. Should I remove the branches that are brown?

David Olszyk

I always remove dead branches. I think they're unsightly and are a disease vector.

Lois Marascia

What is the difference between western red-cedar and Thuja × 'Green Giant'? I was sold trees about four years ago and was told they were western red-cedar. Now, someone is telling me they are Green Giants. How do I know which they are??

David Olszyk

'Green Giant' grows much faster than straight plicata (hybrid vigor). Since the DNA in 'Green Giant' is 50% plicata, they are going to be otherwise very similar.

Jeff Scheidler

I planted 10 Green Giant Thujas back in September 2020. Some of them have some brown areas, but they all have some green on them. I haven't really noticed any new growth yet, but I'm not sure if mid April in NE Ohio is too early in the growing season to see much new growth yet (highs mainly in the 50s and low-mid 60s). What temperatures/time should I start to see some tangible growth?
Also - the soil I believe is likely a lot of clay. When I water, much of the water starts to run off, rather than soak in right away. Would you suggest that I remove the trees and plant with a plant mix, rather than the native soil? If so, suggestions on the proper 'dirt' to use?

Karen Tremblay

We planted 10 'Green Giant' arborvitaes and used some fertilizer spikes and now I read you shouldn't use fertilizer. Some of the trees now have some brown parts. Will using the fertilizer spikes kill them?

David Olszyk

the fertilizer spikes probably won't kill them, they just won't do anything. If you planted 10-foot-tall 'Green Giants' in spring, that's probably what's stressing them.

Ronald Schlak

Jeff Scheidler ,,,Stick with your native soil
It will help to cultivate around your plants to keep the surface rough so water soaks in .
Mulch also helps to keep soil soft

Karen Milligan

David, I purchased 4 Thuja 'Green Giant' that came in the mail, day after Memorial Day, 2021. I followed the directions about the soil, depth of the hole, mulching after I watered them. We live in northern Wisconsin which usually stays temperate. This year, however, became hot right away. 95 degrees for over two weeks! My trees have a lot of brown on them and only the stem and a bit of the branch is at all green. How do I save them? I have watered faithfully early morning and sometimes at dusk. Help!

David Olszyk

Hi Karen ... spring is the absolutely worst time to plant conifers! If you've been watering twice a day without checking if the soil is dry, you probably over-watered and drowned the root systems. If it's been that hot and humid, you've, in essence, poached them.

I think that the odds of them surviving are extremely low. Better to try again in the fall. Trees transplant best when daytime temps are in the 40s / 50s and nighttime temps in the 30s.

Amanda G

Hi David - I’m considering planting Green Giants to address privacy issues on my property. I live in the Piedmont area of North Carolina. My property is mature, native deciduous forest except for a 20’ lawn area adjacent to the house. Without any evergreens on the property, I have no privacy in winter. My neighbor’s house is on higher ground with second story windows overlooking my property. I’d like to introduce some Green Giants to create privacy, but the only sunny space is the lawn area immediately outside the windows of my own home. If I plant the Green Giants in the lawn area, I will create a green wall immediately outside my windows, blocking the view and blocking the southern light. Will the Green Giants grow planted in a mature deciduous woodland? If so, how can I optimize their growth? What would you recommend?

David Olszyk

no need to "optimize" their growth. Green Giants grow extremely fast all on their own.

If by "mature deciduous woodland" you mean deep shade, they will grow very slowly, sparsely and show an equal amount of dead to living foliage. They need full sun to grow as intended.

Anthony Vaccariello

What is the preferred pH for Green Giants? I have 15 Green Giants that have a beautiful glossy lime-green foliage. One is dark green. What is the difference?

David Olszyk

HI Anthony. Google says the optimum PH for most conifers is 5.5 ... The difference between lime-green and dark-green is a few shades of deeper color saturation in the latter. This could be a result of a different cultivar being mixed up in your batch, or that it's gotten itself established quicker.