Canadian spruce

Canadian spruce (Picea glauca) is known to gardeners as gray spruce or white spruce. These names reflect the peculiarity of the needles – its underside has a bluish-white color. The most popular variety of Canadian spruce is Konika. However, in the conditions of the climate, many other varieties are also successfully grown.

The homeland of Canadian spruce is North America, where you can find specimens about 300 years old. Looking at the dwarf varieties of Canadian spruce, which is mainly grown in our gardens, it is difficult to imagine that in nature this is a large tree 25–35 m high, and it can grow even in the harsh conditions of Alaska (1).

Canadian spruce varieties

Nature and the efforts of breeders have given gardeners a lot of beautiful, sometimes miniature, Christmas trees with the most diverse crown shape. Many of them are mutations of the most popular Canadian spruce, Konik. 

The color of the needles of Canadian spruce is not only bluish-blue, but also light green. Small size, soft fluffy needles, color palette – these qualities make it possible to widely use Canadian spruce in landscape design. 

Canadian spruce equally well feels both in a seaside, rather humid climate, and in arid places. However, not all of them grow successfully in many regions. And the reason is not so much in the frost, but in the weak ability to withstand sunburn in the winter and early spring.

Alberta Globe. A miniature plant up to 1 m high with a spherical crown up to 1,2 m in diameter, with delicate bright green needles. It does not just look like Konika, but is a mutation of this variety. 

Frost resistance is average, withstands frosts down to -32 ° С. It grows well in sunny places, but it is quite suitable for places with light partial shade. Needs regular watering and mulching of tree trunks. 

An ideal coniferous plant for rocky gardens or growing in containers.

Echiniformis (Echiniformis). It is considered the most dwarf and slow-growing variety: by the age of 30 it barely exceeds 0,6 m in height and 1 m in diameter. The crown is spherical, but becomes flatter with time, which is why it is often called pillow spruce. The needles are thin and short, greenish-blue.

Frost resistance is average, withstands frosts down to -32 ° С. Needs a bright spot, well-drained soil, regular watering and mulching around the trunks.

An ideal coniferous plant for rocky and heather gardens, mixborders.

These two varieties and Konika are the most popular among gardeners, but you should pay attention to others:

• Blue Wonder) – with a narrow conical crown of a bluish color, by the age of 30 it reaches a height of about 2 m, in a crown diameter – 0,75 m; 
• Rainbows End (Rainbow’s End) – a dwarf plant with a cone-shaped crown up to 1 m high with green needles in spring and bright yellow in summer;
• Sanders Blue (Sanders blue) – dwarf spruce with a cone-shaped crown 0,7 m high with blue needles;
• Daisy’s White – a dwarf plant with a conical crown up to 1 m high, green soft needles, the original yellowish-white color of the new growth;
• Zuckerhut – a plant with a dense cone-shaped crown of bright green color, 1,5 m high and up to 0,8 m in diameter.

Planting Canadian spruce 

All varieties of Canadian spruce traditionally used in gardens suffer severely from winter and early spring sunburn. That is, they need shading. Moreover, artificial shading does not always save. However, planting in partial shade, under the protection of other coniferous crops or dense shrubs, leads to the fact that the needles of most popular varieties lose their bright color.

Therefore, when landing, we must take into account 3 points:

• the tendency of tender needles to burn – you need to find a place where the destructive effect of the bright sun will be minimal;
• average frost resistance of most varieties – the landing site must be protected from cold northern winds;
• surface root system of this species of spruce – in arid regions, watering will be required. 

Having chosen a landing site, it is necessary to prepare a landing pit. It does not need to be made too large, because Canadian spruce seedlings are sold only with a closed root system, that is, in containers. It is enough that the diameter of the pit is 10 cm larger than the earthen coma. However, the depth should be done more in order to arrange drainage on heavy soils, and add clay on light soils.

Spruce is planted with a closed root system during the entire warm period – from April to October. It is important to make a good watering after planting (1 – 2 buckets of water per plant) and cover the soil in the trunk circle with 5 – 7 cm thick mulch. You can use bark, wood chips or stale sawdust of conifers as mulch.

Pay attention to the soil in the container – the presence of multi-colored balls indicates that long-acting fertilizers were used when growing spruce. Therefore, it is enough to put 1 bucket of well-ripened compost in the planting hole.

When planting in the spring on the south side of the seedling for 1-2 weeks, they put supports with a stretched agronet to protect them from the scorching rays of the sun. When planting in late autumn, supports are immediately installed in order to stretch protective screens at the beginning of winter. Shelter from sunburn must be done within 3 to 4 years after planting.

Canadian spruce care

Growing Canadian spruce is simple and easy. The main concern is in the first 3-4 years after planting: you need to properly prepare the plants for the winter to protect them from sunburn. This can be done using a wooden frame on the south side of the tree, on which burlap, agro mesh or non-woven material is stretched. Or tie the plant with spruce branches. An important point: covering materials should not come into contact with needles. 

And in October it is important to make water-charging watering.

Ground

Canadian spruce prefers loamy, humus-rich soils with a slightly acidic reaction. Poor and dry soils, as well as heavy wet ones, require enrichment. Clay is applied on dry soils, and drainage materials on wet soils. Alkaline soils need acidifying fertilizers.

Lighting

The decorative qualities of most varieties of Canadian spruce appear in a high degree of illumination, but in the bright sun in winter and spring, plants suffer from burns – they need protection for the winter. 

Watering

The superficial root system requires regular, but moderate watering and high-quality moisture-charging watering in the fall. Canadian spruce responds very well to dousing with water: in the summer it is advisable to do this once a week. 

Well protects the soil from drying out mulching with a bark layer of 7 – 10 cm.

fertilizers

The application of fertilizers depends on the level of soil fertility. On well-cultivated and humus-rich soils, fertilizers are not required. On fertile soils, when planting, it is enough to add a bucket of mature compost. 

Feeding

Spruces do not require top dressing. However, in the spring, sunburned plants need to be fed with a special fertilizer for conifers. For the fastest recovery of the affected crown, complex spraying is carried out, alternating Epin (2) and Ferrovit preparations.

Reproduction of Canadian spruce 

Varieties of Canadian spruce are grown from cuttings. This is a complex, painstaking and lengthy business.

Cuttings are taken from the lower branches of the tree in late March – early April on a cloudy day. There is a good experience of rooting cuttings taken from spruce trees in the first half of June. The cutting should have a length of 7 – 10 cm and a heel (a piece of trunk bark).

For a day, the cuttings are placed in a solution of a root formation stimulator (Heteroauxin). It is important that only the heel and 1 cm of the lower part of the cutting are in the solution.

Prepared cuttings are planted in cutting boxes or individual pots, deepening at an angle of 30 ° by 2-3 cm. The soil should be light, well-drained (add river sand). The pots are covered with a glass jar, and the cuttings are covered with plastic wrap. 

Rooting can take 6 to 12 months. During this time, you need to ventilate shelters once a day, water the soil in a timely manner so that the soil is always moist. The best option is watering in pallets. Twice a month, add a solution of Heteroauxin or Kornevin to the water for irrigation.

For growing, cuttings are planted in a school organized under the canopy of trees. After 1 – 2 years, plants can be planted in a permanent place.

Canadian spruce diseases

Rust (spruce spinner). The causative agent of the disease is a pathogenic fungus, which can be detected by small orange swellings on the bark. In affected plants, the needles turn yellow and fall off over time. 

To combat the disease, it is important to cut the affected branches in a timely manner and burn them along with the fallen needles. Sick plants should be treated with Hom (copper oxychloride) (2) or Rakurs.

Schütte (brown snow mold). The disease manifests itself in spring, when the snow melts and twigs with whitish needles are exposed. The causative agent of the disease actively develops in winter on branches covered with snow. 

For the treatment of the disease, drugs Hom or Rakurs are recommended (2). 

Tracheomycosis (fusarium). It appears on spruces in the form of a red coating on the needles, which quickly begins to turn brown and crumble. 

The disease is not subject to treatment, since the pathogenic fungus affects the root system. It is important to dig up and burn the diseased plant in a timely manner so that the disease is not transmitted to other conifers in the garden. The soil is disinfected with Fundazol (2).

Canadian spruce pests

Spruce spider mite. This pest leaves tiny yellow spots on the needles, envelops the affected branches with cobwebs and provokes shedding of needles.

Since the tick gives up to 5 generations per season, it is necessary to spray infected plants at least 5 times, especially carefully at the end of summer. You can use drugs Actellik, Antiklesch or Fitoverm. 

Spruce false shield. Leaves a sticky coating on the bark and needles of young plants, causes shedding of browned needles and curvature of shoots. 

To protect plants from this pest, systemic preparations Aktara and Konfidor are used. Actara needs to be sprinkled not only on trees, but also on tree trunks.

Spruce sawfly. The insect infects spruce with larvae that eat the needles, causing it to turn brown and shed. 

The drug Pinocid is most effective against the sawfly – they spray the crown and water the tree trunks.

Coniferous bugs. Small insects with white bristles on the back. In the dry, hot summer months, they multiply rapidly, making infected shoots look like they are covered with frost. The needles turn yellow and curl as a result.

To combat the worm, the drug Pinocid is used.

Popular questions and answers

We asked about Canadian spruce agronomist Oleg Ispolatov – he answered the most popular questions of summer residents.

Sources of

1. Stupakova O.M., Aksyanova T.Yu. Compositions of perennial herbaceous, woody coniferous and deciduous plants in urban landscaping // Coniferous boreal zone, 2013

   https://cyberleninka.ru/article/n/kompozitsii-iz-mnogoletnih-travyanistyh-drevesnyh-hvoynyh-i-listvennyh-rasteniy-v-ozelenenii-gorodov

2. State catalog of pesticides and agrochemicals permitted for use on the territory of the Federation as of July 6, 2021 // Ministry of Agriculture of the Federation

   https://mcx.gov.ru/ministry/departments/departament-rastenievodstva-mekhanizatsii-khimizatsii-i-zashchity-rasteniy/industry-information/info-gosudarstvennaya-usluga-po-gosudarstvennoy-registratsii-pestitsidov-i-agrokhimikatov/