Arbor Vitae - to prune or not to prune the leaders?

[Mia]

I had 5 arbor vitaes planted. I believe they are Emerald Green (not sure). I am hopng for them to grow as quickly anfd full as possible to provide some needed privacy. Unfortunately 3 had to be replaced and are not as full as the originals. It looks like the 3 newer ones have a leader that is shooting up. I read somewhere not to top them or they will stop growing so I am hesitant to do anything. If I prune the leader will it stop the rest from growing? Will it help make the top of the tree grow fuller or is it better to leave then alone? Thanks in advance to anyone who can advise me!

 

[Raintree]

You can snip the tops without harming the plant. You're looking for privacy yet you're reducing height below the window?

 

[TheJollyLogger]

Let the leader grow...

 

[pdqdl]

I disagree. He wants the younger plants to catch up with the older ones.
With just a little bit of trimming can make that happen, and the sooner he starts, the sooner he'll get them looking symmetrical.

Myself, I wouldn't want evergreens blocking my view out the window. Drapes provide better and more complete privacy for windows, and they can be opened.

 

[TheJollyLogger]

I disagree. He wants the younger plants to catch up with the older ones.
With just a little bit of trimming can make that happen, and the sooner he starts, the sooner he'll get them looking symmetrical.

Myself, I wouldn't want evergreens blocking my view out the window. Drapes provide better and more complete privacy for windows, and they can be opened.

He said the newer ones have a leader shooting up...

 

[pdqdl]

I guess that might reveal a bit of ambiguity. I was presuming that the taller plants with the leaders were the ones circled. Unfortunately, we are told about more than 3 plants, but only 2 are pictured, with a tiny corner of a third showing in the background.

I was presuming that tiny corner in the background was one of the shorter versions, but the text suggests otherwise.

In my opinion, emerald green arborvitae should always be kept somewhat trimmed, regardless of how tall you wish for the final specimens to be. Regular shearing will oblige the plant to have a fuller growth habit, and will keep them much closer to the symmetrical shape you desire. Just trim the short ones not quite so much as the taller plants, and they will grow into a nice row of similarly sized plants.

Best to get them about the same size now, because when they are 12 feet tall (or more), folks tend to quit trimming them at all.