How to care for thuja in your garden

Thuja is a long-lived plant, native primarily to southern countries—America and Asia. Despite its heat-loving roots, this conifer has thrived in Russia. Keeping it in the garden is easy, as it's a very undemanding tree.

It can be grown directly in open ground or kept in a pot – in any case, this lovely evergreen plant will become a true decoration of the garden plot.

Plant species

One of the most popular conifers today, there are over 120 different varieties, varying in size, shape, and needle color. Most of these are created by crossing different thuja species. Breeders' interest in this plant is understandable – the demand for such unpretentious beauty is so high. Due to its purely decorative qualities, thuja is often used in landscape design. And for good reason, as it offers numerous advantages:

• the tree does not change its juicy green color either in winter or in summer;
• soft branches with numerous leaves exude a dizzying aroma of essential oils;
• the plant requires minimal costs and effort for care, as it is very unpretentious;
• Thuja pleases the eye for decades.

The most successful among domestic gardeners are the thuja species “oriental” and “folded”.

Thuja orientalis

The oriental arborvitaes (Thuja orientalis) is a coniferous plant known botanically as Platycladus orientalis or Biota orientalis. Commonly found in Korea and China, they grow wild in the steppes on poor soils. These arborvitaes can grow for several hundred years, virtually unchanged in appearance. They develop very slowly, have the form of a regular tree, and reach 5-10 meters in height. In cold climates, they take on the form of a shrub. The crown is wide at the base and very narrow at the apex. The needles are scaly and bright green. Young plants are "prickly," resembling a fir tree. In winter, the oriental arborvitaes (Thuja orientalis) change their color to golden or brown.

Popular varieties

Western thuja (Thuja occidentalis)

This variety is distinguished by its tree's height—up to 20 meters. Its name, "Western Thuja," refers to its origin and native habitat: North America. Its crown, a strict pyramidal shape, softens with age. Its reddish bark is tough, often cracked, and hangs down the trunk. The foliage is dark green and soft. Cones up to 1.5 centimeters long ripen in the fall.

Popular variety

Thuja plicata

In the wild, these arborvitae reach incredible heights – over 50 meters. In our region, plicata arborvitae are not as tall, often reaching 12-15 meters in height – no more. Plants in this group are not known for their frost resistance; often, part of the crown must be pruned due to frost damage. The tree's crown is low, dense, and spreading. The needles are emerald with iridescent colors.

This thuja variety includes approximately 50 different cultivars. All are used in parks due to their vigor and rapid growth.

Popular varieties

Japanese thuja or Standish's arborvita (Thuja standishii)

Native to Japan, it is a moisture-loving plant that thrives in full sun and fertile soil. It tolerates mild frosts well, but is sensitive to drought. It grows primarily as a solitary plant in well-lit areas.

The Japanese arborvitae is a tall, pyramidal tree with a broad base and a narrow apex. The bark is a blood-burgundy color, loose, and peels heavily with age. The needles are matte green with a whitish tint. The wild tree grows to over 20 meters tall. The cultivated variety is modest in size, reaching only 6-9 meters.

Korean arborvitaes (Thuja koraiensis)

A 7-8 meter tall tree or shrub with a conical crown. Naturally, it grows in Korea. It is considered a winter-hardy arborvitae species. The needles are light-colored. Numerous branches are soft and grow at an angle from the trunk. The bark is reddish and rough. Long lateral shoots create a three-dimensional appearance, lending the plant a slightly chaotic appearance, as the thin branches sometimes overlap and "mix." Korean arborvitaes grow on mountain slopes and in coniferous forests.

Caring for thuja after planting

One- or two-year-old arborvitaes can be planted in spring or fall. After planting, arborvitaes need time to establish themselves in their new location and begin to grow. All necessary conditions are created for their successful development: regular watering, soil cultivation, and fertilization.

Regarding fertilizing: during its first year, thuja can grow without additional fertilizers. It thrives on what was added to the soil when the plot was planted. After planting, you can simply stimulate healthy growth, for example, by adding the stimulator "Epin" or using a Zircon solution. These products help protect young plants from pests and diseases and improve the absorption of nutrients from the soil.

It's important to keep the tree's roots moist. Although thujas enjoy water, they don't tolerate standing water, so they're planted in areas with low groundwater, but watered infrequently and generously. A lack of moisture immediately affects the plant's appearance—the tops begin to yellow and wilt. Regular watering can prevent this problem. During the first month after planting, plants need plenty of moisture. Water conifers once every 6-7 days in moderate weather and twice a week during drought, using 2-3 buckets per plant. During wet summers, thujas don't need to be watered—their natural precipitation is sufficient. When watering, use a sprinkler—this will enhance the juiciness and freshness of the leaves, intensify the pine aroma, and clear the branches of dust and make them sparkle. Water the plant early in the morning or late in the evening.

The root area should be kept free of weeds. Loosening the soil will combat these ubiquitous weeds, which also promotes good soil aeration. Experts recommend mulching the plantings to reduce moisture evaporation. Wood shavings or compost are suitable for this purpose. This cover prevents weed growth and, as it decomposes, nourishes the soil with nutrients. Roots under mulch are reliably protected from the scorching summer sun. As a result, the tree thrives and becomes greener with each passing day.

The thuja spends its first two years exploring its new location and getting established. Pruning during this time should be postponed until the tree reaches the desired size and develops a sufficient green crown.

Subsequently, spring care is supplemented by sanitary and formative pruning. Initially, all broken, old, and damaged branches must be removed—this is done in April. Then, the bush is thinned, removing unnecessary shoots and annual growth. Depending on the variety, formative pruning is performed. Thuja can be shaped into virtually any shape, making it a key element of any garden design.

Autumn care and wintering

With the arrival of autumn, the thuja begins preparing for dormancy. Care at this time is less intensive than in spring and summer, but it has its own challenges. By late summer, fertilizing is stopped to curb its growth. Before frost, the plant should slow its life cycle and enter dormancy. This is the only way to protect it from death.

In the fall, garden plants begin to be watered generously, as thujas, although dormant during winter, still develop and require moisture. The final loosening is also done in the fall to oxygenate the soil. Only then is the area mulched with sawdust, peat, or tree bark.

Many people prefer to transplant thuja in the fall. This is a somewhat rash decision, as the plant may not have time to establish itself before winter. However, if you do decide to undertake this important task, experts recommend doing it before the onset of permanent cold weather, specifically in September. Transplanting is done by transshipment, keeping most of the root ball attached to the roots—this way, the plant will settle into its new location more quickly.

The main goal of autumn care is to protect plants from impending frosts. Thuja is a warm-climate plant. Most thuja species don't survive our winters. Therefore, the plant needs to be prepared for the cold season to minimize the risk of frost damage to branches or more significant losses. While temperatures aren't yet too low, covering the base of the tree with spruce branches is sufficient.

For the winter, seedlings up to three years old (and all heat-loving species) require covering. Any non-woven material will do, but it must be breathable and light-permeable and not impede photosynthesis. Burlap can be used, but it won't cover the entire plant. Typically, spunbond is used for covering, or a wooden frame is constructed and covered with material. To make this easier, the branches of the young arborvitaes are tied with rope, pressing them against the trunk. Then, only the plant is wrapped in covering material. The roots are protected with a thick layer (at least 10 centimeters) of mulch made from sawdust, bark, peat, compost, or old grass.

Before covering the plant, cut off yellowed and dried branches, as well as those affected by disease and broken ones.

When warm weather arrives, uncover the thuja. This should be done as soon as the snow is almost gone and the air temperature reaches 15 degrees Celsius. It's important not to delay uncovering the thuja, otherwise condensation will form inside, which will cause fungus to develop. Don't rush, either, as the wood can become sunburned.

As soon as the soil beneath the trees opens up, apply a moisture-replenishing irrigation. The water should penetrate to a depth of up to 50 centimeters, so apply generously. The moisture will quickly awaken the roots, and the plant will begin growing faster.

Spring care

In the spring, active care for thuja begins, which includes several fundamental steps. One of these is protection from spring burns.

Protection from spring burns

As warm weather sets in, clear the snow from the seedlings if they overwintered uncovered, or remove the framework. It would seem that the most dangerous time for this delicate, heat-loving plant—winter—has passed. However, the fine spring days pose many dangers for the plant. The first thing that can seriously damage the trees is strong sunlight. As mentioned earlier, the aggressive ultraviolet rays at this time can damage the young bark. As a result, green branches suddenly turn pale and yellow, and severe burns can cause partial loss of needles. This can be avoided by using a special lightweight covering material, which is applied to the plantings on sunny days.

Trimming

After removing the material, once all the branches have straightened out and returned to their original position, pruning and shaping the bush begins. First, a sanitary pruning is performed, removing all unnecessary branches (broken, dried, or showing signs of disease). Then, the crown is trimmed to shape. Pruning is performed using special pruning shears, which can be used to remove split ends to achieve the desired shape. Consider the tree's location: if the trees are growing in the shade, then during spring pruning, pinch the tops and leave the side shoots alone. This is because the upper shoots stretch upwards in search of sun and need to be restrained slightly. To create a fuller appearance (for example, when creating a decorative hedge), you can pinch all young shoots back by 2-3 centimeters in the spring.

The center of the crown should be well-ventilated. In this case, it's necessary to regularly thin out dense areas, otherwise fungal infections will develop and insects will breed there. Incidentally, birds love to nest in the crowns of fluffy branches, where they breed.

Top dressing

Fertilizing will help your thuja rejuvenate after a long winter. Spring fertilization quickly restores the nutrient balance and nourishes the plant roots, as the soil still has plenty of moisture, meaning circulation isn't slowed down. Mineral and organic compounds, as well as complex fertilizers containing a wide range of essential elements, are suitable for fertilizer. However, it's better to use specialized products for conifers. For example, Zircon will increase the absorption of nutrients and protect against viral diseases, while the equally popular Bioud will supply plants with essential micronutrients. Fertika, a slow-release fertilizer, has a beneficial effect on the plant. It supplies the soil with micronutrients for several months, so if applied in the spring, additional fertilizers can be avoided in the summer. Compost is the most commonly used natural fertilizer.

In general, thuja doesn't require a lot of fertilizer—it can thrive without it, but only if the soil is sufficiently fertile. Fertilizer should be applied carefully, in small doses—high concentrations can harm the roots.

Pest control

In the spring, don't forget about preventative treatment of trees against pests and various diseases. Plants are sprayed with combination fungicides and insecticides to protect against pathogens. The most commonly used products are Fundazol, Rogor, Karbofos (against fungal diseases and scale insects), and Cypermethrin (against aphids and mosquitoes).

Thujas are noted for their high resistance to disease. Fungi and viruses rarely attack the trees, but if signs of disease do appear, they are easily treated.

It's worth noting that coniferous plant diseases are treated quite successfully. The key is to detect them early and address the problem head-on. Spring is the perfect time for this.

Additional procedures

Spring is the ideal time to replant thujas. Generally, it's preferable not to relocate them at all, but this procedure is sometimes necessary. For example, if the seedling was initially planted incorrectly (with the root collar too deep underground), it will naturally fail to develop normally and will quickly wither and die. Once the weather warms up and the soil warms, the plant can be replanted or raised and secured to an optimal height.

In spring, water the plants thoroughly to stimulate the root system. On sunny days, watering once a week is sufficient. During extremely dry periods, water 2-3 times a week. Transplanted trees require more water for optimal establishment. After winter, the soil becomes too dense. Heavy soil does not drain well, causing water to accumulate around the trunk, causing rot. To prevent this, loosening the soil immediately after the snow melts helps. This should be done carefully, as the thuja's root system is shallow.

Caring for a potted thuja

Thuja can be grown indoors, but caring for a potted plant is somewhat different from traditional cultivation. For successful growth, it's important to maintain the correct temperature, especially during winter. Ideal temperatures are no higher than 12 degrees Celsius (55 degrees Fahrenheit) in winter and 18-20 degrees Celsius (64-68 degrees Fahrenheit) in summer. In an overly warm room with dry air, thuja quickly dries out and turns yellow. Therefore, before introducing such a houseplant, it's best to determine whether it can tolerate the temperature. Typically, the shrub is kept on a balcony or veranda during winter, but these should be glazed to prevent the plant from freezing.

Another important factor for healthy plant growth is proper lighting and location. The thuja should receive consistent sunlight, but not direct sunlight, but diffused light; otherwise, the leaves will burn and begin to fall off. The shrub should be placed near a window on the north side of the house, but it should be covered with tulle. In the shade, the plant will stretch out, becoming unsightly and dull. Avoid placing the pot near heat sources, as this can cause the plant to dry out.

A potted arborvita requires consistently moist soil. Overly dry soil will prevent the shrub from developing fully, and it will simply stop growing. Regular watering twice a week is essential for a houseplant. If the air is too dry, mist the crown to keep the leaves green and lush.

Thuja thrives in a loose, nutritious soil mixture of leaf mold and coarse sand. For mature trees, a mixture of turf, peat, and sand is used. Fertilize infrequently, alternating mineral fertilizers. In the spring, you can apply a single nitrogen fertilizer, and in the summer, add potassium-phosphorus compounds. Indoor thuja is almost never affected by disease. It is also well protected from pests. However, this is no reason to neglect the health of the needles. Shoots and leaves should be regularly inspected, and if disease is detected, be sure to prune out affected areas and treat with a fungicide. Saving the plant, even if the disease has just begun, can be done quickly and without unnecessary losses.

Growing thuja in a pot requires annual repotting. Because the plant's root system grows extensively, choose a tall but not too wide pot with a drainage layer at the bottom to allow excess moisture to drain. Mature thujas are repotted every two to three years.

Potted thuja is primarily decorative. Due to its flexible and malleable crown, the shrub can be shaped into any form with skillful pruning. Oriental thujas typically have a pyramidal shape, but they can be shaped into a ball, a cone, or a spiral—it's all up to the owner's discretion.

Thuja, like any other plant, requires care. When caring for it, don't neglect fertilizing, watering, and protecting it from freezing during the winter. By creating comfortable growing conditions, the thuja will delight its owner with its beauty for decades.