GG only grow that fast in a greenhouse .. and denver aint no greenhouse.. lol

if you are zone 5.. then think in the 12 to 24 inch growth rate ... with your 5 months of winter soil temps ...

and trees.. of which conifers are. NEVER stop growing.. and using a ULTRA BIG tree. and wishing it would stop at 10 feet is not going to happen ...

ken

i dont really wish they stop growing, was just wandering if trimming them every year back 1' or whatever they grow previous year to keep them at certain height/shape is going to harm them. thanks

Top them at 10 ft.

Of course that will mean 2 trips up the ladder ever year to maintain that sheared hedge look for 37 ft. Don't go there with 'Green Giants'.

The 7 ft. wide strip is really not enough width even if you sheared them. They will eventually overwhelm that area.

Slower growing Thuja occidentalis 'Smaragd' AKA Emerald Green is more suitable. Your best bet to control height and width proportions from shearing. They make a great hedge if done properly.

Plant 36 inches apart.

Dave

dave, we have neighbor that has privacy fence strip(in fact continuation of where we want to plant)made out of emerald greens. they just would not grow and they split with every bigger snow we get. he has to bound them for every winter which helps a little, but seems like they have multiple trunks and just go crazy in all directions with snow load. also he said he planted them 3 years before we moved next door, about 2 years ago. said he bought them 3' tall, and now after 5 years they are barely 4' tall. i was talking with him and we want to use something faster growing. either green giants, or maybe spartans would be better as they grow more compact.

You can prune any tree to what ever size you want.
However there are consequesses. Keeping a tree limited to 10 ft will first be physically difficult, how will you trim a 10 tree unless you have a tall ladder.
Next as ken said Trees continue to grow. And trees that grow fast will mean as they approach the ulitmate height, you will have to take off more each year. I beleive pruning stimulates growth, and creating mulitple branch development ( like you see when trees are topped) As you top those arbs additional branches at the top will grow, making more work for you each year. Finally there is always the problem of the one dead arb in the 35ft row of 10 ft arbs and how do you replace it.

Maybe consider slower growing shrub or if you have room a groups of different shrubs, Some large some smaller.

Or maybe some plants closer to the house or a fence.

Just some throughts to think about before you buy 25 arbs

Mike

Green Giants also lose branches when under high snow load, then you have holes there in their appearance. A little over my property line my neighbor has Green Giants, after 15 years or so they are 10 ft wide and 20 ft high. I try to cut my side and notice that when I cut too far on a branch, the foliage does not grow back, sticks remain. They become in spots a real eye sore - on my property...

My Smaragds though behave well also under snow loads, never require shearing, 10 ft tallx 3 ft wide. They also stay on my property.
Bernd

Thuja occidentalis 'Wintergreen' - if after 28 years a height of 35' is to tall, then not the right plant. They grow up to 14" per year.

Also sold as: 'Hetz Wintergreen' & 'Wintergreen Pyramidal'.

Space them every 3 feet for a quick screen or 4' for still, a quick screen.

Dax

Here is a link that might be useful: Evergreen Nursery

thanks, wintergreen might be even better than spartan as it seems to be more tolerant of shade. last 2 trees planted in the strip will not get full sun.

'Hetz Wintergreen'

A single leader conifer that will not look good topped at 10 ft. or at any height.

Has good vertical accent and columnar in nature. Probably the best selection if you leave it to free range.

Dave