Thuja standishii x plicata 'Green Giant' / Green Giant 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!

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.

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.