I'm planting 5 gallon (they are about 3' ~ 4' from the bucket up) Thuja Green Giant next to my fence for privacy. Any suggestions on how close to plant them to the fence. I plan to space them 4' apart from each others.

Hi scp_ok,

Years ago I wanted to plant Leyland Cypress (LC) on my property line for privacy, but didn't want to infringe on my neighbors property. I took the mature diameter of the LC avg. 7' divided by 2, added a little extra, and planted them 4' from the line.

So, according to that logic, and this site U.S. National Arboretum: Gardens: FAQs: 'Green Giant' Arborvitae (http://foxyurl.com/4LH) , 4' from the fence would be okay, but your plan of 4' centers would be 2.5' too short.

If planted too close, your TGG's will have stunted side growth until they reach the top of your fence.

I know these will grow very tall and thought perhaps the 4' centers (to make sure I'm saying the right thing that is them being side by side) will control the height as they will be closer together. They are for a privacy hedge so don't really need them much over 12' so figure the close they are planted the less final height they will get. Is my understanding. Is that a correct statement.

Sorry No. By the very name of your specimen, Giants, it is genetically predisposed to grow tall, in fact crowding may introduce competition that could kill them.

I am looking at planting the same thing. I seem to remember reading 6' on center. Not sure about the fence distance, my fence will be coming down when the plants are that high.

Hi! Shipswake

If you check the link above, 3rd paragraph down it says on 6½' centers, and then it grew to 8' diameter.

Try these two sites for added information Conifers: Thuja Green Giant arborvitae, us national arboretum, thuja green giant (http://foxyurl.com/5hu)
PlantFiles: Detailed information on White Cedar, Eastern Arborvitae, American Arborvitae, Northern White Cedar Thuja occidentalis (http://foxyurl.com/5hy)

And finally Check this link for a lively discussion on planting too close, Green Giant Arborvitae Advice - GardenBanter.co.uk (http://foxyurl.com/5hA)