Arborvitae, popular evergreen trees and shrubs, are a common choice for creating privacy screens and enhancing landscape aesthetics. Understanding their typical lifespan is important for anyone considering them for their property. These plants offer year-round visual appeal.
Average Lifespan of Arborvitae
The average lifespan of arborvitae can vary significantly, generally ranging from 25 to 150 years in cultivated settings. Some arborvitae in the wild have been documented to live for hundreds of years. However, the lifespan in a typical yard is often much shorter than in their native habitats.
Specific cultivars also exhibit different longevity expectations. For example, ‘Emerald Green’ arborvitae typically has an average lifespan of about 25 years. In contrast, ‘Green Giant’ arborvitae, a hybrid, generally lives between 40 to 60 years. These variations highlight the importance of considering the specific type of arborvitae when assessing its potential longevity.
Factors Determining Lifespan
Several elements influence how long an arborvitae will thrive. Environmental conditions play a significant role in their overall health and longevity. Arborvitae prefer moist, well-drained soil, with loamy soil being ideal as it balances moisture retention and drainage. A slightly acidic to neutral pH range is optimal for nutrient absorption. Adequate light exposure is also important, with full sun (at least six hours of direct sunlight daily) promoting denser growth, although partial shade is tolerated.
The genetic makeup of different arborvitae varieties contributes to their inherent lifespan. ‘Emerald Green’ and ‘Green Giant’ varieties have distinct longevity patterns. These genetic predispositions mean some cultivars are naturally more robust or resistant to certain issues than others, influencing their potential to live longer. Choosing a variety suited to the local climate and conditions is an important step in promoting longevity.
Proper care practices are also important for extending an arborvitae’s life. Consistent and deep watering is necessary, especially during the first few growing seasons, to establish a strong root system. While they need consistent moisture, overwatering can lead to root rot. Applying a balanced, slow-release fertilizer in early spring can promote healthy growth. Minimal pruning is needed, but light shearing in late spring or early summer can help maintain shape and remove any dead or diseased branches.
Common Challenges to Longevity
Arborvitae face several threats and stressors that can shorten their lifespan. Pests and diseases are significant concerns.
Pests
Bagworms are a common pest that can defoliate plants, with larvae constructing spindle-shaped bags from needles. Spider mites, tiny arachnids, cause yellowing or bronzing of needles and produce fine webbing, often thriving in hot, dry conditions. Scale insects also drain fluids from plants, leading to yellowing needles and a sticky substance called honeydew.
Diseases
Fungal diseases like root rot, often caused by oversaturated soil, lead to wilting and yellowing leaves. Tip blight and needle cast are other fungal issues causing needles to turn pale green, yellow, or brown.
Environmental stressors can impact arborvitae. Prolonged drought, extreme heat or cold, and urban pollution can weaken plants. De-icing salt can cause damage, particularly to foliage near roads or sidewalks.
Heavy snow and ice accumulation can break branches, especially on young or multi-stemmed plants. Winter burn, characterized by browning foliage, can occur when water evaporates faster than the plant can absorb it from frozen soil. Deer browsing is another common issue, as deer are fond of arborvitae, particularly when other food sources are scarce in winter.
Improper planting techniques also contribute to early decline. Planting arborvitae too deep or too shallow can hinder root development and water absorption. Compacted soil around the root ball restricts root growth and drainage. Circling roots can continue to girdle the tree’s root system even after planting.
Maximizing Your Arborvitae’s Lifespan
Strategic planting is the first step toward promoting a long life for arborvitae. Selecting a site with full to partial sun and well-drained, loamy soil is important. When planting, dig a hole two to three times wider than the root ball and ensure the top of the root ball is level with or slightly above the soil surface to prevent issues like root rot. Backfill the hole carefully, gently tamping to remove air pockets, and water thoroughly to settle the soil.
Consistent care practices are important for ongoing health. Arborvitae are not drought-tolerant and require regular, deep watering, especially during their establishment period and in dry weather. Mulching with a 2-3 inch layer of organic material around the base of the tree, keeping it a few inches from the trunk, helps retain soil moisture, regulate temperature, and suppress weeds. Fertilization can be beneficial in spring with a balanced, slow-release product, but over-fertilization should be avoided.
Proactive management of pests and diseases helps protect arborvitae from damage. Regularly inspecting plants for signs of pests like bagworms or spider mites allows for early intervention, such as hand-picking or using appropriate treatments. Addressing issues like root rot often involves improving soil drainage and avoiding overwatering. Pruning away diseased sections promptly can prevent the spread of fungal blights.
Winter protection is necessary to prevent environmental damage. Tying up multi-stemmed arborvitae with twine in late fall can prevent branches from splaying and breaking under heavy snow or ice. Applying anti-desiccant sprays can help reduce moisture loss from foliage during cold, dry, and windy conditions. Burlap wraps or fencing can offer protection against winter winds and deer browsing. Ensuring plants are well-hydrated before the ground freezes also helps them withstand winter stress.