Coniferous Tree Care: All you need to know about Leyland, Thuja, Goldcrest and Arizona cypress

Coniferous trees are probably some of the most popular choices in garden design. These species are widely used as ornamentals due to their relatively small requirements and to the peculiarity of their foliage, which makes them ideal choices for landscaping. The most popular pattern of coniferous trees is the development of a privacy fence. A privacy fence will help shield your home from neighbors and thus maximize your privacy. 

The types of conifers that can be used as ornamentals are various. However, not all of them are suitable for all purposes. 

On the market, we can find conifers suitable for creating a green backdrop for fencing, delimiting an area or even protecting an area from wind and dust. In some cases, they are even effective for acoustic insulation. Below we will describe some of the most commonly used evergreen conifers that are suitable for gardens and squares.

Which conifer to plant in my garden? – Conifer trees examples for Gardening

Thuja

The plant is suitable for:

• High and dense privacy fences (as long as we do not choose dwarf varieties)
• Individual planting in the garden
• Planting in pots

Thuja Characteristics:

Thuja (Thuja orientalis) is an evergreen ornamental coniferous plant. It is a member of the Cupressaceae family. In many species, the height of the plant can reach up to 18 meters (59ft). However, the varieties mostly are of medium height and are mostly found as shrubs or small trees. More specifically, the most commonly preferred Thuja species are Thuja occidentalis (or T. pyramidalis pyramidal Thuja) and Thuja orientalis. The plant blooms, but its flowers are very small. As coniferous, the seeds of the plant are kept inside small oval yellow cones.

Where to plant my thuja

The plant can withstand a fairly wide temperature range from -25 ℃ to +32 ℃ (-13 to 89.6 ℉); however, at higher temperatures, it begins to have problems.

As for the soil, the plant does not have special requirements. It grows well in all soil types, even in relatively arid soils. It prefers cooler areas but also thrives near the seaside.

Leyland

Very popular plant suitable for:

• Planting Individually in a garden
• Planting in pots
• Apartment greenery
• Dense and high privacy fences

Leyland Characteristics:

Leyland (Cupressocyparis leylandii) is one of the most popular ornamental conifers. It is a very fast-growing evergreen conifer that forms a dense pyramid-shaped crown. Late in spring or early summer (May-June) the plant blooms, however, its flowers are small.

Where to plant my Leyland

The plant can withstand a fairly wide temperature range from -25 + to +28 ℃ (-13 to 82.4 ℉), but at higher temperatures, it begins to have problems. As for the soil, it does not have special requirements, it grows well on all soil types, even on poor and rough soils, as long as they provide sufficient drainage.

Goldcrest

Plant suitable for:

• Planting individually in a garden
• Building Fences (Privacy fences)
• Planting in pots

Goldcrest (Cupressus Macrocarpa Goldcrest) is another evergreen coniferous of the Cupressus cypress family. The leaves of the plant have a lemon aroma. It is quite often the most preferred ornamental tree in many countries, as it has very impressive foliage. It also blooms during late spring, but its flowers are very small. Depending on the variety, the planting area and the tree care, it may reach a height of 12-15 meters (39.3-49.2 ft) or more.

Where to plant my Goldcrest

It is not recommended for planting in hot regions, as it is likely to encounter problems at very high temperatures. 

Arizonica or Arizona

Plant suitable for:

• Planting individually in a garden
• Privacy fences 
• Suitable also for wind protection

Arizona (Cupressus arizonica) is a coniferous evergreen native to America, characterized by a fairly rapid growth rate. Its shape is narrow conical and can reach a final height of 10-15 m (32.8-49.2 ft) or more. It is one of the most adaptive plants and is widely used in the creation of tall fences and windbreaks, as its dense foliage significantly blocks the wind.

Where to plant my Arizona

Arizona can withstand very low temperatures reaching -25 ℃ (-13 ℉). It exhibits good tolerance to high temperatures in summer as long as they do not exceed 30 ℃ (86 ℉). It has no particular soil requirements. It adapts in a variety of soils, even in barren areas, provided they have sufficient drainage.

Conifers Growth Rate – Who Wins? – Which conifer grows bigger?

Many people ask about the growth rate of these plants. The answer is that the champion is definitely the Leyland. About 1-2 years after planting, Leyland begins to grow at a rate of 120 to 140 cm (3.9-4.6 ft ) per year, under optimum conditions. The other species mentioned above can also grow quickly. For example, Arizona under favorable conditions can gain about 100 to 120 cm (3.3-3.9 ft) per year in height. Goldcrest and pyramidal thujas can also gain up to 60 cm in height per year. However, during the first year, as long as they are still young, coniferous try to develop their root system. During this period, they may not have noticeable growth in height, leaving gardeners disappointed. Nevertheless, in the upcoming years, and as they mature, their growth can be really impressive. Even thuja can grow up to 2 meters (6,6 ft.) per year, yet, from the tenth year onwards. In any case, if we want to build a dense plant fence immediately, we will need to buy tall trees (2.20 meters or 7.2ft or more), and plant them at a distance of 1 meter (3.3 ft.) away from any paddock, keeping at least 1 to 1.2 meters (3.3-3.9 ft) distance between the trees. 

How do I take care of conifers in my garden? 

Soil preparation for coniferous planting 

Before planting a tree in the garden, it is often necessary to properly prepare the soil. This preparation involves cleaning the area, usually by applying good tillage around the planting area using special tools. Tillage aims to remove weeds (which compete with young trees in water and nutrients) and to remove stones and any unwanted material from the soil. At the same time with this technique, we try to soften the soil, making it suitable to welcome the sensitive roots of the young tree.

Following the soil preparation, we should dig planting holes. The pits may have different dimensions depending on the trees species we are going to plant. In most cases, we buy ornamental conifers from the nursery in pots. Thus, a general rule is to open planting pits 20 to 50 cm (7.9-19.7 in) in diameter and depth bigger than the size of the pot.

How and When to Plant Conifers – How to create a privacy fence using conifers

Transplanting of ornamental conifers is usually performed in the fall or even early in winter in most areas. We usually buy the plants from nurseries in pots and transplant them to their final positions, after we have properly prepared the soil. Conifers are planted together with the soil ball they already have from the nursery. In many cases, especially if our soil is particularly barren, it would be good to mix the soil in the pit with well-digested manure, compost or synthetic fertilizer prior to planting. 

Then, we grab the tree from the trunk and gently press the pot so that it falls onto the ground, revealing the soil ball. This procedure requires special care, as the roots of the plant should not be injured. Furthermore, it is very important not to break the ball of soil. For this reason, we should not try to pull the plant out forcefully, nor should we cut the roots that may have become entangled on its bottom. It is very important to place the plant in such a way so that its trunk is straight. In many cases, we will probably need a little tree support, especially during the early stages after transplanting. For this reason, we place a support stick next to the tree trunk and fasten the tree gently on at two to three points.

If we wish to plant more than one conifer in the same area, we should keep proper distances between them. The planting distances can vary significantly, depending on the coniferous species, the climate conditions and the soil of the area. Of course, the purpose for which we plant the tree and the shape of it are also important parameters. Broadly speaking, the appropriate planting distances are those in which we find each tree in nature. So if we want to plant two conifers, a piece of good advice is to place them at least 2-3 meters (6.5-9.8ft) apart, so that they can grow properly. 

However, if we want to make privacy fences, things are different. We should take into consideration the type of tree we have chosen together with the rate of its growth. A sparse planting will result in a very slow growth rate of the fence, causing unattractive gaps between the plants. On the other hand, very close distances may impede the growth of the plants, due to intense competition among them, something that will result in improper aeration and drying of the branches. Some examples of planting spaces for different conifers are: We plant Leyland, Arizona and other species with a similar growth rate, keeping at least 1 m (3.3ft) distance from a fixed barrier (e.g. paddy). In case you use them for fencing, we keep 1 to 1.5 m (3.3-4.9 ft) distance between plants.

Irrigating Coniferous – Do Conifers need watering? How Much Water do Conifers Need?

Coniferous trees come from forests where temperatures are fairly low. For this reason, in order to survive in a garden, they need regular watering, especially during the summer. Generally, during the winter when rainfalls are frequent, we offer additional water to the plants only if it has not been raining for more than a week or when we notice that the ground is completely dry. On the other hand, during the summer period, water requirements regularly increase. Conifers need irrigation at least 2-3 times a week during this time. In case of extremely high temperatures (heat waves), we may need to irrigate the plants even daily (during the evening). During months of intense heat, our conifers are likely to express their need for water by drying their foliage. We should, however, be very careful with irrigation. It is true that those plants have an increased demand for water during summer, but on the other hand, they should never be found in flood conditions. If so, there is an increased risk for the plants to be infected by threatening diseases such as Phytophthora. In any case, you may avoid watering the foliage, as there is an increased danger for infections. The best method in most cases is to install an automatic irrigation system. Although in most gardens, we tend to use sprinklers as an irrigation method, it would be wiser to use a drip irrigation system. Apart from helping significantly in water-saving and precision irrigation of the tree, it also offers an important advantage to conifers. It prevents water from coming in contact with the foliage. This is very important, as it significantly reduces the risk of fungal diseases.

Conifers Fertilizer Requirements – Best Fertilizer for Conifers

In general, these species adapt quite easily even to poor soils. However, it is advisable to help them grow in height and width, by adding fertilizer.

Broadly speaking, the most suitable fertilizer for garden conifers (Leyland, Arizona, Thuja and Goldcrest) contains more nitrogen than phosphorus and potassium (e.g. 18-8-8). Nitrogen is a critical element for these species. Other fertilizer types are also acceptable; however, the amount of nitrogen shall be equal to, or greater, than phosphorus and potassium. Additionally, our fertilizer may include trace elements (calcium, magnesium, iron, copper, boron, manganese and sulfur). You may consider applying a slow-release form of the fertilizer. The majority of these types of fertilizers are found in water-soluble form. The best time to apply fertilizers to conifers is early spring (March – April). A slow-release fertilizer applied for 6-8 months in early spring will provide the conifers all the nutrients they need throughout the season. We can also apply a water-soluble fertilizer once or twice a year starting early in the spring. It is advisable not to apply slow-release fertilizers during summer, as the plant may grow very rapidly from late summer to autumn (August to early October). Thus, it will have to harden (to create extra plant tissue) so as to tolerate the cold during winter.

We can also increase the soil nutrients by simply adding manure or compost. When it comes to manure, we can mix 1 kg (2.2lbs) around each mature tree, but be careful because manure should not touch their trunk. Synthetic organic fertilizer, on the other hand, is applied directly into the soil in an amount of 200 gr (0.44lbs) per square meter. If our conifers are in pots, then we can apply 1-2 handfuls of manure per pot. However, these are just common patterns that should not be followed without making your own research. Every field is different and has different needs. You can discuss it with a local licensed agronomist. 

Conifers pruning – When and how do you prune a conifer tree

Many of the conifers we choose for our garden need pruning not only for aesthetic reasons (shaping) but also for maintaining the health of the tree. These species, although selected as ornamentals, come from forests with low temperatures and have a very rapid growth in most cases. If we leave such a tree unpruned for long periods, it would not be surprising to see it evolve into a green giant. In many cases, these trees reach or even exceed 30 meters (98ft) in height. Of course, this will take many years to occur, but it is advisable to regulate its development early. In addition to regulating tree growth, pruning helps towards proper aeration and rejuvenation. Diseased, underdeveloped or dried branches should be removed to promote new vegetation. In addition, the continuous growth of unpruned conifers causes the foliage to form gaps at its center due to the thinning of the vegetation. This is something undesirable, especially when the plants are used as natural hedges and privacy fences.

We can easily shape the majority of conifers from their earliest stages of development, by using simple pruning shears or electric brush cutters. However, in the case of mature and tall trees, telescopic chainsaws are generally used. Chainsaws allow the cutting of tall branches from the ground. Since we are not talking about fruit trees in which we are interested in maintaining a desired fruit set rate, pruning here is much simpler. Basically, we simply adjust the size and shape of the tree by reducing the length of its branches.

The preferred pruning season for conifers is late autumn to early spring. We may need to intervene again during summer to improve their shape, so as to prepare them for winter. It is wise not to prune our conifers during days of extremely high temperatures (summer), as this will cause problems.

As far as pruning methods and shapes are concerned, these vary according to the type of conifer, the reason for its installation and the opinion of the owner. For example, for individual conifers in the garden, a common practice is to remove the branches 20-30 cm (0.6-0.9ft) from the ground so as to ‘strip’ the trunk and leave it bald near the ground. This, among other things, protects the foliage from soil diseases. The branches should always be cut very close to the trunk carefully in order to avoid injuring the trunk. Furthermore, it will probably be necessary to remove certain thicker branches that grow within the plant.

People often form these trees into artistic shapes. However, this requires great care as there is a risk of causing shock to the plant. One general rule is to make sure that a large percentage of green branches remain on the tree after pruning. We should not prune the young shoots of the tree by cutting over 10 cm (0.3ft). We can easily identify young shoots as they have different, usually lighter colors. 

It is clear that not all species need pruning in the same frequency and intensity. Some species grow at very high rates and require more frequent interventions, while the slow growth rate of others allows us to delay pruning. Goldcrest needs perhaps the fewer interventions, on which we only remove some peripheral branches in order to maintain its shape. On the other hand, we can prune Leyland heavily without causing problems to it. If not pruned properly or at all for years, Arizona will end up having an uncontrollable, unmanageable shape due to its increased growth rate.

When pruning conifers, it is crucial to have basic personal protection. Nowadays we can find on the market special safety glasses, so as to protect our eyes during pruning. We will also need a pair of good gloves that will protect us from hand-cuts and injuries. 

Conifers Pests and Diseases 

Conifers are quite tough trees. However, they do encounter some problems with pests and diseases, like all other plants.

The main enemies of the Conifers are the various Coccoidea species with pseudococcus to be the most important of them. They cause significant damage to the plant, while at the same time they produce honey-like secretions that promote the growth of fungi, causing serious consequences to the plant. In cases of infestation, pests are visible on the foliage, as they are white and resemble cotton. If the infestation is severe, the plant foliage dries out. Plants are more susceptible during days of high temperature and humidity levels. Poor foliage aeration naturally worsens the situation. Leyland, Thuja and Gold Crest are the most susceptible to these infestations. In order to prevent such a situation, make sure not to irrigate the foliage of the plants, especially during summer. Also, it is wise to prune the plants properly for better aeration. You can try to remove insects when the problem is still limited manually. If the problem goes beyond control, you will need to consult a licensed agronomist.

Furthermore, these plants are susceptible to fungal infections. The most common and important pathogen that infects conifers in the garden is the Phytophthora sp. This fungus lives in the soil and infects the root system of the plant, causing serious damage that, if not treated during its early stages, can lead to the death of the plant. In cases of fungal infection, we will observe dry foliage that may be mistaken for water stress. Dry and brown foliage starts from the parts of the plant that are near the ground. The best method to manage the disease is always prevention. We avoid very dense plantings, excessive moisture near the root of the plant, foliage wetting, and we often check for problems. Leyland is one of the most susceptible conifers to Phytophthora. As soon as we notice changes in our conifers or if there is an outbreak of the disease in the area, it would be advisable to consult a licensed agronomist in order to discuss actions, for instance spraying with chemicals. Infected plants should be removed immediately from the garden.