Correct Spacing for Thuja Green Giant

Thuja Green Giant is the most popular screening and hedging plant for a wide area of the country. It is so fast-growing that an attractive, durable screen or hedge can be created in a few short years. When planning to plant a screen or hedge, how far apart you are going to place your plants is the first decision you must make. Spacing depends on several factors, and it is going to have a big effect on how soon you have an effective screen, and how durable that screen is going to be. It is definitely worth putting some serious thinking and planning into this step, before purchasing your trees.

Why Close Planting is a Bad Idea

The most common mistake made is putting the plants too close. This becomes more of a problem the taller you want your final screen or hedge to be. It is always tempting to go for an ‘instant hedge’ and pack the plants as closely as you can in the row. This might give a quick effect, and for a shorter hedge it can even work out OK, but it usually just creates future problems instead. One obvious problem is that by packing the root balls together, there is no room for future root development, so the plants become stunted and starved for food – meaning slower growth over the long term. The second problem is that plants naturally compete with each other for light, so by crowding them together they grow tall and skinny, and the lower branches quickly die, leaving your hedge bare and thin.

A tall thin hedge is also much more likely to bend over or even break in a storm, strong winds or a blizzard. The thin stems just can’t hold up the branches once they are weighed down with water, ice or snow. That is that last thing you want to happen to your hedge, so you need to encourage sturdy growth, and to do that means allowing the plants more room.

Choose the Right Spacing for the Result You Want

Grown as a single plant, Thuja Green Giant will be about 12 feet across in 12 years or so. That means that a screen even at that spacing will eventually form a solid barrier. Most of us don’t want to wait that long, so something closer makes sense. In trials that were done at the University of Arkansas, very small plants were 5 feet across in 7 years, meaning that the typical 4-foot or 5-foot tree bought for a screen or hedge will be that wide in just 2 or 3 years. So, if you space your plants 5 feet apart you will get the best combination of sturdiness and speed to complete your screen. If you have more time, or less money, then spacing between 5 and 10 feet wide will always give you a solid screen, some just take a little longer to get there.

For hedges, closer spacing is best, because you want a denser surface to trim it into that beautiful solid, green hedge you are dreaming of. This means that for hedges, spacing your plants between 3 and 5 feet apart will give you perfect results in a very short time.

Single or Double Spacing?

The answer to this question depends on how solid you want the barrier to be, and how much space you have. Double spacing – where we plant two rows, not one, with the plants staggered in the rows to create a zigzag pattern – is the best way to get a really dense screen that will block wind, noise, dust and drifting snow. It will be wider, so you need more room, and it takes a few more plants. However, since the spacing in the rows is increased, it actually doesn’t take a whole lot more plants at all. For example, if you are planning a single row spaced 5 feet apart, then a double row, with the rows 3 feet apart, and the plants 8 feet apart in the rows, still gives you plants that are 5 feet apart on the diagonal. (Some quick school geometry with Pythagoras’ Theorem will prove that). This means that for a 150-foot screen, you need 30 plants with single spacing, and only 8 more for a double row. Those few extra plants will give you a really solid and dense screen just as quickly, and a superior result in the long-term.

Planning and Planting Your Hedge

The first step is to measure out the length you want your hedge or screen to be. Then try dividing that length by 5 for a screen, or 3 for a hedge – how many plants is that? Let’s take an example. I want a hedge that is 123 feet long. If I divide that by 3 I find I need 41 plants. If I go with a wider spacing of 4 feet, that number comes down to 31 plants. Is the saving worth the slightly longer wait for that perfect hedge? Only you can answer that question.

Once your plants arrive, and you are ready to plant – something we have looked at in other blogs here – it is important to place all your plants in their final location before beginning to plant. Put the first and last plants half your chosen planting distance from the place you want the hedge to end, and then place the plants in between. Adjust the positions so that every plant is evenly spaced BEFORE you start planting.


Thinking about spacing in the planning stage, and making the right decision before you place your order, is time well-spent, and will give you the best possible result for your investment. Thuja Green Giant is a tough, adaptable plant, but it will give you its best if you help out with a little planning. You will soon have that screen or hedge you have been dreaming about.