Arborvitae (Thuja spp.) are evergreen members of the cedar family and are native to the eastern two-thirds of North America. Translated from Latin, the name means ” tree of life” Eastern Arborvitae (Thuja occidentalis) is sturdy across USDA zones 2 to 8 and is most commonly planted. Giant Red Cedar (Thuja pilcata) is sturdy over USDA Zones 5 to 8 and can be widely planted. Both are widely tolerant of a wide range of climate and soil conditions, but perform best in well-drained, loamy soil with a rather impartial pH.
Importance of pH
Soil pH is a main concern when planting arborvitae. Acidic soils have a lower pH value, from 0.0 to 6.9, and alkaline or basic soils have a higher pH value, from 7.1 to 14.0. A value of 7.0 indicates neutral soil. Essential nutrients in the soil are more readily available to arborvitae origins once the soil pH falls at an optimal range of slightly acidic to slightly alkaline. Nitrogen, potassium and phosphorus are most easily transferable in soils with a pH selection of 6.0 to 8.0, as are most secondary elements such as iron, magnesium, sulfur and copper.
Testing Soil pH
Prior to planting, a soil test will identify your land’s pH. The best pH for arborvitae is 6.8 to 7.2, as stated by the University of Texas in Austin. However, many members of the species will tolerate a pH range from acidic to alkaline, according to the Ohio Department of Natural Resources. Highly acidic soils may be neutralized to the desired pH with lime or dolomite. Highly alkaline soils can be neutralized with sulfur derivatives.
Improving Problem Soils
Arborvitae specimens will flourish when planted in soils that are high in organic material and well-drained. If your soil is loam or sandy loam, then it may not need to be amended. However, silt beds or tight clay soils may be improved with the incorporation of organic matter. Working at a 3- to 4-inch layer of compost, aged manure and melted pine bark to a depth of 18 inches will help get the tree’s roots off to a strong start by increasing aeration. This practice will also improve transport of pH-adjusting alterations more extensively by improving drainage.
It is also important to site your arborvitae nicely. Thuja species and cultivars are tolerant of a mild quantity of shade but favor growing in full sun, if possible. Always dry soils or areas that are densely shaded are not conducive to healthy development. Arborvitae selections can range in height from 8 feet to more than 150, so look at the mature height you’d like to achieve with your plantings and choose varieties carefully.