Do I Need to Trim Thuja Green Giant?

Thuja Green Giant is a plant for everyone, and that includes those who don’t like gardening. Many people are willing to prepare the soil, and plant, but after that they just want their plants to take care of themselves, while they turn their attention to other important matters, like family, or golf. If this sounds like you, and you have been considering using Thuja Green Giant for a screening plant, to hide that ugly view and enclose your garden. Maybe you are not sure, because you see so many examples of this plant used for hedges, where the owners trim once, twice, or even more often each year. You don’t want to do that, so how do you decide if it will work, and what are the limitations of not trimming?

Do You Have the Necessary Space?

Because we see this plant trimmed into hedges so often, we can be forgiven for not realizing it is a potentially large plant. Since it is fast growing, it will reach full size in a relatively short time. You can expect a minimum height of ten feet from small plants in no more than 7 years. If you start with plants in the 4 to 5-foot range – a good starting size – then in 7 years they will be 15 feet tall. The original plant, which was grown at the National Arboretum in Washington, was over 30 feet tall just 25 years after being planted as a tiny plant a few inches tall. That 30 feet is usually given as the maximum height, but all evergreens grow just as long as they are alive. They grow more slowly, but you can expect your plants to eventually exceed even 30 feet. If you aren’t going to trim, ask yourself if a screen that tall is too much. Remember that it will throw a long shadow for most of the year, apart from the few months of summer, when the sun is high in the sky. If you plant it to the south of your garden, it will give you a lot of shade – maybe you want that. If you plant it to the north, next to a neighbor, then they may not want your shade on their garden.

How Wide Will Thuja Green Giant Grow?

Consider too that a single plant can become 12 feet wide when mature, so a screen of untrimmed trees will be 12 feet thick. The best advice is to plant your screening row of trees 6 feet inside your property line, unless your neighbor(s) agree that you can plant it closer. That way the trees are always on your property, and there is no danger of disputes. Check too with your city. If you are in town, it is possible that there are height limitations of hedges and screens, and if so you should choose a shorter plant for an un-trimmed screen.

Considering this width, it makes sense to plant your trees 6 to 8 feet apart, so that you will have a solid screen in a few years. If you are planting a specimen, then give it a space at least 15 feet across, so that you can enjoy its mature appearance without it looking crowded. Don’t plant in front of windows. If you have 8 to 10-foot ceilings, then the windows on a third floor will be blocked in time. Don’t plant too close beside a door. You should place the trees 6 feet or more away from the edge of the door opening. Rely on your measurements, even if you think it looks too far away – remember they grow fast! Some people plant ‘by eye’, but unless you are experienced with outside distances, you will probably judge it wrongly, and end up having to trim after all.

Careful measurement is much more important when your goal is to not trim your trees. You may have plenty of room, but getting the position just right is the key to avoiding trimming – make a mistake and don’t allow enough room and you will be up that ladder with the hedge trimmers very soon.

Are There Any Risks to Consider?

If you live in an area where fire is a risk, that is something else to consider. If your trees catch fire, you don’t want them to spread that fire to other trees, or even worse, to your home. In fire-prone areas it is best to plant all taller trees so that their outer edges are at least 30 feet from your home, or outbuildings. If you have a sloping garden, then on the downward slope allow 100 feet, as flames will burn uphill more rapidly. Again, go out and actually measure the distances – don’t risk your property for a few minutes work.

All This Sound Great to Me

If you have thought about all this, and you see no problems fitting plants of this size into your garden, then go ahead. Now you have planted them, after careful measurement and placement, just sit back. Thuja Green Giant grows into a beautiful, dense, upright tree, of charm and character. It is resistant to salt spray, rarely nibbled by deer, and sturdy enough not to be blown down in regular storms, either rain or snow. Even if the branches do get weighed down with ice or snow, when it melts they will spring back up, and the form will be restored.

Remember that an unclipped screen will be more ‘natural’ looking. It will have a looser, informal look, and the top will not be perfectly flat and even. It will look great, it just won’t be a formal hedge. Many people think it is more beautiful when allowed to grow naturally, and whether you plant it as a screen, or as an individual specimen in a lawn, this is the perfect tree for that natural look.

Maybe Just a Little Trimming. . .

There is a good argument to make for doing some trimming while your trees are growing. If you do it right, it does not commit you to a life behind a hedge trimmer, but it will give you better looking plants for life. When a fast-growing plant like Thuja Green Giant is young, it is common for several shoots to compete and give several tall growing points on your trees. Each one will develop into a ‘mini-tree’, and give a more open, wider plant. You can easily produce a more tapered, narrower tree with a little formative trimming.

Here is what to do. Select a tall shoot in the center of the tree and leave it untrimmed. Cut back the tops of all the other shoots so that the tall one is at least 3 feet above the others. On a taller tree, make that 6 feet. As you move towards the outside, cut the stems shorter. Always cut back to an inward-facing shoot if you can, as that will keep the form tighter. You can repeat this process once or twice more as the tree grows. The result will be a lovely, flame-shaped tree with lots of elegance, for almost no work. Never cut back so hard that you leave a bare, leafless branch. It will not re-sprout, and you will have spoiled your tree.

In fact, that last point is the main reason why you need to consider carefully before letting your trees grow untrimmed. Once they are tall, it is hard to make them shorter again, because you can only trim back to areas of green growth. It is easy to grow Thuja Green Giant untrimmed. It just takes a little foresight and planning.