Deciding on which plant to use as a hedge or screen is a big decision. Its appearance is going to be a major part of the backdrop to your garden, and its success will pave the way for success with the plants protected by it. This means it is worth taking some time to make sure you have made the right decision. Thuja Green Giant is currently the most popular hedging and screening plant, across most of the country. It has earned that position with its toughness, adaptability and speed of growth – all areas where it excels. But that doesn’t mean it is right for everyone, so let’s look at the different parameters that you should consider when making your final choice.
What climate zone do you live in? The Green Giant is happy anywhere from zone 5, where winter lows can fall to minus 20 degrees Fahrenheit, all the way into zone 9, where winter lows dip just a little below freezing, to plus 20 degrees, and then only for short periods. So if it sounds like you live in that broad belt, you have made the right choice. If you fall outside those zones, then there are better choices open to you. The Emerald Green Arborvitae, a selected form of the Eastern White Cedar, is as hardy as it comes, living happily when winter lows dip to a polar-bear friendly minus 50 degrees. This plant makes a great hedge, and should be your choice for cold areas.
If, at the other extreme, you live where it rarely if ever freezes, and you want an evergreen hedge with the fine texture of Thuja Green Giant, then the Italian Cypress, Cupressus sempervirens, should be your ‘go to’. The hotter the better for that plant, and it needs no cool winter period to keep it healthy, as the Green Giant does. It does thrive best in hot, dry climates, like southern California. In the heat and humidity of southern Florida, an even better choice is the Leyland Cypress, or the Spartan Juniper. Speaking of Junipers, if you live in a very dry area, where watering is going to be a problem, then give some serious thought to the Arizona Cypress, Cupressus arizonica ‘Carolina Sapphire’. This tree produces an extremely drought-tolerant and striking hedge.
Here things are easy. If you have almost any kind of soil, from a very sandy one, all the way through to sticky clay, Thuja Green Giant will perform well. In very dry soil you may need to water more often, and the only problem could be in very wet soils. This great tree is happy in soil that is wet from time to time, but not if it is permanently flooded or always saturated. Over time, this will lead to problems, so if you have this problem where you need a hedge, consider something surprising. Most people know the Bald Cypress, Taxodium distichum, which grows wild in the Everglades, among other places. It can be clipped into a formal hedge easily, and makes a gorgeous, soft-textured screen. It will grow right in shallow water, and flooded soils are just what it loves best. The only disadvantage is that it loses it leaves in winter, leaving instead a dense screen of branches. This is attractive too, but doesn’t give the same level of privacy.
Sun or Shade?
Consider how much sun your plants are going to get. Remember that shade from deciduous trees is not a problem in winter, and in summer, when the sun is high, they cast only a narrow shadow. If your Thuja Green Giant hedge gets sun for half the dy from spring to early fall, then it will be perfectly happy. It will grow well in full sun too of course, so unless you have a deeply shady area where you need a hedge, you will be find with this versatile tree.
Should you find that you do need a hedge for deep shade, there are several choices. For a finer texture, nothing beats the Canadian Hemlock, Tsuga canadensis. This shade-loving evergreen has soft, fine leaves that clip into a superb hedge, even in areas that get no direct sun at all. Other choices include the various Yew Trees, that also make dense hedges in all conditions, from full sun to full shade.
You Need a Fast-Growing Hedge
If this is your need, then you certainly have made the right choice. In trials by the University of Kansas, who weren’t selling anything to anyone, Thuja Green Giant grew faster than any other plant they tested in a large study. From small plants, they grew into upright columns10 feet tall and 5 feet wide in the space of just 7 years. That is remarkable, and means that with a growth rate of 3 feet a year in the early years, most of that growth in height happens in 3 to 4 years. After that your hedge or screen with thicken and fill in, especially if you trim it lightly from Day One. A regular annual trim, or perhaps twice a year if you want a very neat hedge, is all that is needed once you have established the height and thickness you want. The only mistake some people make is to let their hedge just grow and grow, until suddenly they realize it needs more than just a trim. Sadly, if you cut back into wood that has no foliage, those branches will not sprout, and all your work will be wasted. Begin to trim lightly from the first year, including on the sides, and build a dense structure, adding height at ‘only’ a couple of feet a year. The top-quality result you see will show you it was worth it.