Question
My husband and I recently purchased Thuja Green Giants. We are curious about their root systems. We have cinderblock fencing all the way around ( standard for our neighboorhood) we bought this tree to add as a privacy fence all the way around. Our planting instructions told us to plant the trees 5 feet apart, so we did. However we planted them 2/12 feet from the wall assuming the 5 feet was also in diameter.

We received a letter from our HOA stating trees need to be planted 5 feet from the wall, however if we consult an expert on the specific tree we planted, less would be fine.

So our question is. Will the trees that we planted 2/12 feet from the wall, disrupt the wall? Or be harmful to the tree? If so, do we need to dig them up and replant? They have been planted 1-2 weeks now. They are small..only 18 inches - 2 feet.

Also some of them are bent way over, do we need to worry about staking them straight yet?

Im sorry about all the questions, we have researched online alot and found no answer to these.

Thank you for your time.

Answer
Planting them 5 feet a part would make a hedge look and as a screen that would be best. These have a width at maturity of 12 -16 feet meaning the branches will reach about 6-9 feet from the trunk. So you can expect the branches along the wall to touch the wall which is not a bad thing.

The root will spread about 1 to 1 1/2 times the width of the branches but they are fibrous and will not damage walkways, foundation or walls.  You will not have any trouble with the roots damaging the wall.

The 2 1/2 feet will work fine as long as you understand the branches will grow against the wall and you will not be able to go behind the tree and the wall. But as far as this distance hurting the tree or the wall I would not think there would be any problems.

The drooping of a tree this small is due to too much or too little water. They should be watered not more than every third day. You can stake them and with trees this small I would run a stake maybe a dowel down beside the tree and tie it with a soft material loosely to the tree until the roots get settled  (take the stake up next spring).
I hope this answers your question If not write back,