 Thuja Occidentalis "Green Emerald" Arborvitae are probably the first plant that you think of when you hear “evergreen screen”. Arborvitaes can be tough, easy to deal with garden plants and with a little creativity, you can avoid another boring row of Emerald Green Arborvitae. I’ll admit it. There’s something nice about a mature, well spaced row of arborvitae. The first person who created one of these hedges must have thought they were a genius but now you can’t walk down a suburban sidewalk without seeing an arborvitae hedge in nearly every yard. The more common something is, the less special it becomes. With something like landscaping, there are endless possibilities so there’s no need to plant the same plants in the same manner, over and over and over again.  Northern White Cedar at the UofM Arboretum Wild plants are usually referred to as cedar and landscape varieties are typically called arborvitae but they are the same plant and share the Latin name Thuja. Until a few decades ago, pretty much all thuja planted in the midwest were variants of thuja occidentalis. The wild plant is called Northern White Cedar and it’s a 30 to 70 ft tall tree that gets about 15 ft wide. It grows naturally in the northeast US and southeast Canada in swampy and moderate moisture areas. I love Northern White Cedar but it has its problems and is rarely used as a landscape plant in Ann Arbor any more. 70 ft is taller than most people want in a small yard and it is a deer favorite making it hard to establish in larger yards. I rarely see the species plant at nurseries but the variants “Hetz Wintergreen” and “Pyramidalis” have very similar appearances but tend to top out at around 30 to 40 ft tall.  Thuja Ocidentalis "Pyramidalis"  Thuja Occidentalis "Techny" There are a few varieties that stay on the shorter side including “Emerald Green”, “Techny” and “Nigra”. Emerald Green is the most common type and has a very uniform shape ending up at about 5 ft wide and 25 ft tall with a dense, vibrantly green foliage. Techny tends to get about 15 ft tall and 10 ft wide and is a good option for a screen when you don’t want the height. Nigra tends to look more natural and have darker foliage than the other two. It has a looser habit and gets 20 to 30 ft tall. There is also Globe arborvitae. I have only seen thuja occidentalis types of globe arborvitae but there could be others as well. Globe arborvitae grow in a spherical shape and are typically under 10 ft tall with some only growing to 2 ft tall. The old fashioned variety is “Woodward” but there are now many varieties including some with yellow/golden foliage. These are great for small yards and foundation gardens.  Thuja Occidentalis "Golden Globe" In the last few decades, a new type of arborvitae has been growing in popularity. The most common variety is “Green Giant” and it’s a cross between Thuja Plicata (Western Red Cedar) and Thuja Standishii (Japanese Arborvitae). Both Thuja Plicata and Thuja Standishii are listed as hardy in zone 6 but I don’t really see them planted which makes me think they have problems with our climate. Green Giant as well as“Spring Grove” and “Steeplechase” do well in Michigan and are less likely to be eaten by deer than varieties of Thuja occidentalis. Green Giant arborvitae grow quickly to 30 to 60 ft tall. These plants can grow 3ft a year after they’ve established a root system! Green Giants are often sold by garden centers as 2 ft plants with tags that say “30 ft” tall. These will often be 30 ft tall after 10 years or if planted closely together in a hedge. It wouldn’t surprise me if many Green Giants grow much taller than they are expected to, like many Northern White Cedars that were planted close to buildings 50 years ago.  Thuja Plicata X Standishii "Green Giant" on UofM Campus Arborvitae have a lot of great characteristics that can come in handy when designing a garden space. If you’re going to use them, consider using something other than “Green Emerald” and planting with other plants mixed in or in a staggered pattern to help differentiate them from every other “Green Emerald” hedge in the neighborhood.
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