When planting for privacy, how close together should they be?
To grow an unbroken hedge you should space the plants no further apart then their mature spread.
This is usually about 20 to 25 feet.
If each plant reaches 20 feet and spreads 10 feet on either side; two hedges will eventually meet in the middle of a 20 foot spacing.
You can plant closer together--7 to 12 feet without any harm and they will form a more tight hedge.