they are called GIANTS.. because.. well.. they get giant ... they will not stop at your height requirement ... and they will get very wide at the bottom ...

do you have the space at ground level.. for something giant???

perhaps a pic of the situation.... will get you better advice ...

ken

Can't tell you how well they do in extreme heat - although a similar zone, that only refers to winter cold temps, not anything to do with summer! And it just doesn't get that hot here in summer for more than a day or two at most. Anything in the 90's is a rare event!

But you should be aware that if they do grow well for you in Houston, they will get a LOT bigger than 15-20 feet!!

20FT is the minimum I'd like. I don't have a problem if they grow 30-40 FT tall.

I have a 8ft easement from the back fence to the pool, in which I'd like to plant them. I'd remove the italian cypress, yews and shrubs I have back there now. thanks.

8' is too narrow for GG's. They will have a base spread of 15' or more once they start growing well.

thanks for your reply. https://www.fast-growing-trees.com says width is 5-8 ft when mature.

Sorry but they are incorrect! Most sources will state 10-12' after 10 years and wider with more time. In my climate, you can see GG's with a 25' base spread.

You can keep tighter with shearing but that's a big PITA if you have many.

fast growing trees.. are fast to grow.. fast to over grow.. prone to damage due to fast growth ... and as trees.. NEVER stop growing ... unless they collapse due to the above ...

i would NEVER rely on a site thats base marketing ploy is fast growing ...

as such.. what they said is blatantly wrong .. and of no value to you ....

at very good sites.. all estimates are at 10 years ... and you can presume at 20 years... they will be twice as big ...

and for a shiny penny i will tell you how i really feel ...

ken

thank you both: @gardengal48 (PNW Z8/9) , @ken_adrian Adrian MI cold Z5 - if possible, please provide your sources. I'd like to read them as mine say 8ft wide x 35ft tall.

I'm still looking for answers to my questions:

has anyone planted thujas GG in Houston?

how fast do they grow in this area?

how tolerant are they to Houston heat?

I’ll just answer the heat question: they do fine. No heat issues at all, ime.

Texas here, had three in full sun at my last house ... triple digits for weeks every summer. Mine thrived and grew fast, never had any browning.

My primary source is my personal experience with these trees in my area but check any reputable horticultural source for correct specs - extension services, MOBOT, National Arboretum, etc. And they won't stop at 35' tall either!! Several planted in the 90's at a former nursery I used to work for are now maybe 40-45' tall and a good 20' wide at the base. And that was several years ago (5?) when I last saw them....no doubt appreciably larger now.

here is how i look to future potential ...

https://duckduckgo.com/?q=thuja+Green+Giant+size&t=ffcm&iar=images&iax=images&ia=images

this MI boy knows nothing about TX ... your on your own with that part ...

my primary source is the 100 i planted on my 5 acres ... being a member of the conifer society.. and my collection of 500 plus conifers that i grow ... in MI ....

good luck ... i gave what i can provide ...

ken

please provide your sources. I'd like to read them as mine say 8ft wide x 35ft tall

Plant sizes given by commercial sources in particular for trees and shrubs are often based on comparatively short periods of time such as 10 or 20 years - I've even seen a 10 year size called "mature", as if woody plants didn't often live for decades (or centuries).

And of course no woody plant growth except individual bamboo canes grows quickly to a specific height and diameter and then remains frozen there, without continued increase occurring throughout the life of the plant.

http://hort.uconn.edu/detail.php?pid=501

http://hort.ufl.edu/database/documents/pdf/tree_fact_sheets/thuplia.pdf

Have you heard of thuja gardens? thoughts? I called and emailed them, but no answer.

https://www.thujagardens.com/product-page/thuja-green-giant

The primary difference between the many arborvitae cultivars (Thuja occidentalis) is the shape and limits. Green Giant is one of the older varieties that tends to sprawl. Skybound has been the best in my experience for staying columnar, with a height/width ratio of about 4:1. In your climate however, some of the cypress cultivars may be better.

All cedars tend to sprawl some. Giving them a haircut, trimmng off the bits that stick out will keep them neat. This gets difficult once they outgrow your step ladder.

Please place a photo I want to plant some in SA TX

Curious to know why want to replace the Italian Cypress trees, and if you did, how did the Thuja Green Giant turn out?

Italian cypress trees are best suited to dry, warm climates, so they could struggle in soggy heat common to the Houston area, not to mention the gumbo clay typically found in the region. They're also susceptible to certain diseases and pests, and there was serious damage reported after the severe winter of 2020-21.

My experience with Thuja "Green Giant" is confined to the Midwest/Upper South so I can't speak to how they do on the Texas Gulf Coast. As far as spacing goes, if they're being planted for a privacy screen/tall hedge they can be spaced 5-10 feet apart; for an extra-thick screen you can plant them in staggered rows 5 feet apart or so. Eight feet of space between a pool and the property line should be no trouble. Hedging plants can eventually be trimmed if needed.

Specimen trees (Green Giants look great in this role) should be given more space, but most people use them for screening so tighter planting works well.

We had a couple of staggered rows of Green Giants at a previous home that grew well and looked beautiful as a screen. When we sold the place, the new owners cut down all but one of the trees (apparently they didn't like the privacy). That one tree had been partially compressed against a neighbor, and while it looked fine as part of the screen it did NOT make a good appearance as a solo tree.

Did you planted them in Houston?
How did they do during the summer?
Did they survive weeks above 100F?

I'd skip. Unless you can buy older trees? I planted about 20 of them I got from that fast growing trees place. Started at 12 inches about half a dime thick. They were fine for 3 years then we got hit with the Texas heatwave of 2023. Lost them all. They didn't make it. Despite watering everyday. The trunk was already the size of a 50 cent piece give or take. Temps hit 110+ in Dallas. I'd say it was a devastating loss. Other plants survived like hibiscus, roses, canas, shrubs, bigger trees like 60 year old pines. Not these youngsters.

I'd skip. Unless you can buy older trees? I planted about 20 of them. Started at 12 inches about half a dime thick. They were fine for 3 years then we got hit with the Texas heatwave of 2023. Lost them all. They didn't make it. Despite watering everyday. The trunk was already the size of a 50 cent piece give or take. Temps hit 110+ in Dallas. I'd say it was a devastating loss. Other plants survived like hibiscus, roses, canas, shrubs, bigger trees like 60 year old pines. Not these youngsters. Best of luck.