How to take care of blue spruce trees


How to Grow and Care for Colorado Blue Spruce

Colorado blue spruce (Picea pungens) is a coniferous evergreen tree with sharp and short needles that belongs to the pine family. The official state tree of Colorado, this slow-growing spruce is native to the Rocky Mountains, where it was first discovered in 1862. In the wild the Colorado blue spruce can grow up to 75 feet tall. In parks and gardens it usually tops out from 30 to 60 feet high. Colorado blue spruce is one of the most widely used trees both for holiday decorations and landscaped backyards. Its pyramid shape, silvery-blue foliage color, and wonderful smell make it a classic choice for a Christmas tree. Then, when the holidays are over, seasoned gardeners like to use the tree's boughs to make a shrub shelter to overwinter garden bushes.

The best time to plant a Colorado blue spruce tree depends on your climate. You can plant spruce year-round in mild climates, but if you live in an area with harsh winters and frosts, it's best to plant this tree during the late winter or early spring (late February through April), when it's dormant. If you plant blue spruce in the early fall, there's a chance it will become susceptible to winter injury and die-back.

Common Name Blue Spruce, Green Spruce, White Spruce, Colorado Spruce, Colorado Blue Spruce
Botanical Name Picea pungens
Family Pinaceae
Plant Type Tree
Mature Size 75 ft. high, 15-20 ft. wide.
Sun Exposure Full
Soil Type Loamy, clay, sandy, moist, rich, well-drained
Soil pH Acidic, neutral
Hardiness Zones 2-7 (USDA)
Native Area North America

Colorado Blue Spruce Care

An established Colorado blue spruce tree is easily maintained, as it only needs regular watering when it is first planted. Providing 2 inches of garden mulch around the base of the tree helps it retain moisture in between waterings or during drought years. Spruce trees benefit from a high-nitrogen fertilizer once a year in the form of compost, and they thrive in areas with several hours of filtered sunlight a day.

The Spruce / Adrienne Legault

The Spruce / Adrienne Legault

The Spruce / Adrienne Legault

Light

Plant Colorado blue spruce trees in full sun, ensuring they get at least six hours of unfiltered sun per day to reach their full growth potential. Blue spruce can tolerate some shade, but planting in a low-light area can increase disease incidence and severity.

Soil

A spruce tree grows best in a location with moist, well-drained soil made fertile through the use of soil amendments. However, this tree can adapt to a variety of soils—loamy, sandy, or clay. As for soil pH, spruce thrive in a range between 6.0 and 7.5, but its unfussy nature makes this tree able to tolerate extremely acidic or alkaline soils.

Water

Once established, this tree is drought-tolerant and can survive periods of low water, but it thrives with scheduled waterings. During the first season, water the tree regularly to keep the soil moist. Once the tree is established, water it only during dry spells. Avoid waterlogging the tree or creating areas with standing water at its base.

Temperature and Humidity

A native to high mountain areas, Colorado blue spruce is tolerant of dry, cold weather. Still, this tree variety can tolerate heat and humidity better than other spruces. Blue spruce will not thrive in extremely hot conditions, however, as its needles will turn brown and fall.

Fertilizer

These trees do not need frequent fertilization. That said, spring fertilization will give the tree an added nutrition boost and likely increase the length of the needles and improve needle color. Sprinkle 10-10-10 slow-release granulated fertilizer over the soil in the root zone. Then, water with about 2 inches of water to prevent fertilizer burn. Better yet, use a natural and pet-friendly option like compost, fish emulsion, cottonseed meal, or alfalfa meal, to avoid burn altogether. For fertilizer amounts, follow the product label instructions.

Types of Colorado Blue Spruce Trees

Colorado blue spruce comes in several varieties, all with beautiful silvery-blue needles:

  • Picea pungens "Baby Blue Eyes" is a semi-dwarf cultivar that grows 15 to 20 feet tall.
  • Picea pungens"Bakeri" features a deep blue color and grows 12 to 20 feet high.
  • The dwarf variety Picea pungens "Glauca Globusa" grows 3 to 5 feet high, 3 to 6 feet wide, and rarely produces cones.
  • Picea pungens "Moerheimii" has branches that droop and grows to a maximum of 30 feet tall.
  • Picea pungens "Montgomery" is another dwarf variety that grows 5 to 6 feet high and has dense, blue needles.

Pruning

Colorado blue spruce has a slow to medium growth rate, growing less than 12 to 24 inches annually. This tree does not need to be pruned, but can be if you want denser foliage. In this instance, prune off half of the fresh growth on each candle (the tip where branch growth occurs each year) in the spring.

Propagating Colorado Blue Spruce

Colorado blue spruce grows well from cuttings taken mid-summer and then planted in the fall. Cuttings take a while to root (two to three months) and need to be treated with a strong rooting hormone. Grow cuttings in cool and humid conditions for successful propagation. Here's how:

  1. Gather your garden shears, an alcohol wipe, a paintbrush, a potting container, peat, medium-grit sand, 0.6-percent indolebutyric acid rooting talc, and a spray bottle.
  2. Combine equal parts peat and sand in a bucket. Cover the mix with water and let it sit until the peat swells. After that, fill your potting container with the mixture.
  3. Clean the blades of your shears with alcohol and cut a tip 4 to 5 inches long from one of the tree's side branches. Make an angled cut between two sets of needles.
  4. Strip the needles from the bottom half of the cutting and peel the bark from the end. Brush the end with rooting hormone.
  5. Poke a hole in the potting container equal to half the length of your cutting. Insert the cutting into the hole and backfill it with the peat mixture.
  6. Place the pot in a cool indoor spot with filtered light. Avoid direct sun.
  7. Drizzle water regularly onto the peat's surface, and mist the air above the cutting, allowing the water to fall onto the needles.
  8. Check for roots after two months (it could actually take up to four months to root), and then move the pot outside into direct sun to acclimatize for a week, bringing it in each night.
  9. Transplant the cutting into the ground in early autumn by digging a small hole, placing the baby tree and the contents of the pot into the hole, backfilling it, and then spreading a thick layer of mulch around the base. Water the tree regularly for three years until it's established.

How to Grow Colorado Blue Spruce from Seed

With patience, Colorado blue spruce can be grown from seed after collecting and drying pinecones to obtain the seeds. Come spring, soak the seeds in water for 24 hours and then wrap them in a moist paper towel and store them in the refrigerator for six weeks. Next, place a seed in a container filled with moist seed starting mixture, cover it with 1/4 inch of the mixture, place plastic wrap over the container, and relocate it to a sunny spot. Keep the mixture moist until the seed germinates and grows about an inch, then remove the plastic wrap. In all stages of growth, Colorado blue spruce is slow so this may take a while. Harden off the seedling by bringing it outside into direct sunlight for several days. Transplant the seedling to the ground once it's acclimatized, mulch around the baby tree, and water regularly for three years.

Overwintering

Colorado blue spruce is native to cold climates, therefore established trees do not need special care in the winter, as the tree will go dormant during this season. You can, however, spread a layer of mulch around the tree's base in the fall and wrap its trunk in burlap to protect it from hungry animals. Also, make sure to shake the branches after a heavy or wet snowfall to prevent them from snapping due to the snow's weight.

Common Pests & Diseases

The two most common issues affecting Colorado blue spruce trees are fungal blight and beetle kill. Among the pests, they are also affected by aphids and the Cooley spruce gall adelgid. The former will cause the needles to grow yellow blotches and become sticky, while the latter can be identified by the presence of a cotton-like substance on the spruce's branches. To ward off pests, hire a company to spray the tree with a non-toxic horticultural oil that won't endanger birds, pets, or humans.

This variety of tree can also be affected by disease, the most common and destructive of which is Cytospora canker. This fungal disease typically moves into trees that are 15 to 20 years or old, causing the needles to turn brown and drop from the branches. Cytospora canker is a stress-induced disease, so manage it by amending the soil regularly and not overwatering.

Common Problems with Colorado Blue Spruce

While blue spruce trees need ample watering during the first several years, it's easy to overwater them with this mindset. Signs of overwatering include browning needles, wilting branches, and die-off. To prevent this from happening, make sure the tree never sits in standing water, and provide ample mulch to keep moisture around the tree's base, allowing you to go longer in between waterings.

Article Sources

The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. Blue Spruce: Common Health Issues in the Landscape. University of Massachusetts Amherst Extension Landscape, Nursery and Urban Forestry Program.

Care and Maintenance of Colorado Blue Spruce Trees | Home Guides

By Susan Lundman Updated March 15, 2018

Standing tall and regal with blue-green foliage, Colorado blue spruce (Picea pungens) makes a majestic specimen tree, whether you grow it outdoors or take it indoors as a Christmas tree. Also called Colorado spruce or blue spruce, this gorgeous tree is low-maintenance. It grows up to 100 feet tall in the wild, and nursery trees reach 60 feet tall. Dwarf varieties grow 2 feet tall. Colorado blue spruce grows best in U.S. Department of Agriculture plant hardiness zones 2 through 7.

Light and Water Needs

Colorado blue spruce thrives in full sun but also grows in partial shade. Once established, the tree needs a medium amount of water, with a deep soaking every two or three weeks. Even though the tree likes the soil to remain moist, especially while it's still young, it's also tolerant of drought. Mulch around the tree's base beyond the width of the tree to help retain moisture in the soil and keep the roots cool.

Feeding Needs

A slow-release fertilizer designed for trees helps keep your Colorado blue spruce healthy. Follow these guidelines when applying fertilizer:

Call your utility company before making holes in the soil around the tree so you don't hit any pipes or wires buried in the ground.   Because the tree's roots are fairly deep into the soil, you need to make small, 1- to 2-inch holes in the soil with an iron bar to a depth of 12 to 18 inches. The holes help ensure that the fertilizer reaches the roots.   Follow directions on the fertilizer label for your tree and mix the fertilizer with sand or compost to insert it into the holes.
Apply fertilizer once a year in the fall.

Damage From Pests 

Colorado blue spruce is relatively resistant to pests, and they probably won't kill your tree, but they can do some damage. Look out for these insects:

Spider mites are the most serious pest your spruce may have, and they could affect the overall health of the tree. If the tree's needles turn yellow they may be infected. Examine the tree for the mites on the yellowed branches. If the tree is small, hose off the mites with a strong spray or use an insecticidal soap or a chemical insecticide for a large infestation. Follow the directions on the product. Gall-forming insects come in a variety of types, but they all produce small bumps or growths that may look like miniature cones at the tips of branches. Galls will not harm your spruce. Other pests that cause minimal amounts of damage include spruce budworm, spruce needle miner, pine needle scale and aphids.

Diseases

Except for canker problems in the East, Colorado blue spruce doesn't suffer serious damage from diseases. If you live in that area, also plant a white fir (Albies concolor), which grows in zones 3 through 7.

These are the most typical diseases:

Canker turns needles brown before they drop off and produces white patches on branches that have been infected. To treat the disease, cut off infected branches and avoid overhead watering to keep the foliage of your tree dry. Sterilize your pruners after use to be sure you don't spread the disease to other trees.
Needle casts and rust both turn needles yellow or brown and cause them to drop off, but these diseases don't cause serious problems.

References

  • Missouri Botanical Garden: Picea Pungens
  • This Old House: Ailing Blue Spruce
  • Missouri Botanical Garden: Galls on Trees
  • Missouri Botanical Garden: Spider Mites -- Outdoors
  • Missouri Botanical Garden: Albies Concolor

Writer Bio

Susan Lundman began writing about her love of gardening and landscape design after working for 20 years at a nonprofit agency. She has written about plants, garden design and gardening tips online professionally for ten years on numerous websites. Lundman belongs to numerous gardening groups, tends her home garden on 2/3 acre and volunteers with professional horticulturists at a 180 acre public garden where she lives on Bainbridge Island in Washington State.

Planting and caring for blue spruce - Landscape Design Studio

CONTENT OF THE ARTICLE:

1. Blue spruce: varieties and types

2. Preparatory work

spruce after planting

Due to the unusual color of the needles, Blue Spruce always stands out on the site against the surrounding background. Its second name is Prickly. Tetrahedral needles, directed from the shoots in all directions, are really dense, hard and prickly. Planting and caring for Blue Spruce is slightly different from growing Common Green Spruce. A young blue herringbone requires more attention and care.

Blue Spruce releases more phytoncides than Common Spruce, so its aroma is much brighter and thicker. In terms of intensity, it can only be compared with the Siberian cedar. For the sake of this, it is worth growing a Blue Spruce in the country.


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The unique color of the tree is given by the wax coating secreted by young needles. Different types of spruces have different concentrations of plaque, which affects the color saturation. By autumn, rains and winds erase part of the wax, the color of old needles shifts towards green. Young cones at the ends of the shoots have a bright color: pink, lilac, purple. Growing up, they turn green, and when ripe, they turn brown.

spruce Iseli Fastigiata

Blue spruce: varieties and types

More than 60 decorative forms of prickly spruce are used in landscaping. Ordinary trees are large, pyramidal, 20-30 m high. But Blue Spruce varieties are undersized, shrubby, wide-crowned, creeping.

According to the color of the needles, three groups of forms are distinguished:

  • Coerulea (coerulea) - blue;
  • Glauca (glauca) - gray;
  • Argentea (argentea) - silver.

There are changing variegated specimens.

Argentea
Koerulea
glauka

Blue spruce varieties are grown from large trees:

  • Bonfire - up to 10 m, pyramidal crown, neat, horizontal branches, needles 25 mm, does not change color.
  • Hupsi -10-12 m, pyramidal crown, horizontal branches, dense, needles 25 mm thick, one of the brightest varieties.
  • Fat Albert - 10-13 m, the crown is even, pyramidal, the branches are dense, directed slightly upwards, needles up to 1 cm, bright blue in spring and green in autumn.
  • Izeli Fastigiata -10-12 m, crown is even, narrow pyramidal, compact, branches are densely stacked, directed obliquely upwards, needles 2 cm, bluish-green. Similar varieties with a narrow crown of Izely Foxtail and Blue Totem (spiny blue).

Other tall forms for landscaping: Hoto, Oldenburg, Omega, Moerheim 10-15 m, Iseli Snowkit up to 10 m, Thomsen up to 12 m.

spruce Bonfire
spruce hupsi
spruce fat albert

Popular low-growing varieties:

  • Glauka Globoza - 1-2 m, crown is dense, wide pyramidal, with a flat top, young silver-blue needles, adult blue. The tree lends itself well to shearing, it is often formed into a ball.
  • Blue Kiss - up to 1.5 m, dense crown, spherical, even, short shoots, blue needles.
  • Blue Pearl - up to 1 m, the crown is round, dense, blue needles.
  • Maygold - up to 6 m, crown is pyramidal, loose, branches are horizontal, young needles are creamy golden, becoming bluish-green in summer. Varieties with similar properties of needles Golden Feathers, Stanleys Gold, Fryulingsgold.

Landscape design uses undersized and dwarf varieties Blue Trinket, Brynek, Mekki, Kompakta, Edith, Lucky Strike, Frida, German Nau.

Spruce Glauka Globoza

Planting Blue Spruce: Preparatory Work

Planting Blue Spruce should be planned in a sunny area. Then the trunk will grow even, the crown is symmetrical, the branches are dense, the needles are fluffy and bright.

Spruce perishes from standing water. If the area gets wet, the planting hole should have good drainage. If the planting of the Large Blue Spruce is planned, the site will have to be drained.

Spiny tree does not like dense clay soil. It has a shallow root system. If the roots cannot penetrate into the depths, the tree will die during a drought or be uprooted by strong winds. In breathable soil, it develops roots in width and depth, increasing its wind resistance.

Conifers prefer slightly acidic soils. If the soil on the site is limed, the planting of the Blue Spruce should be preceded by acidification of the soil. Suitable ammonium nitrate, ammonium sulfate, ammonium chloride in small quantities. High-moor peat, coniferous litter and sawdust, sphagnum moss gives a slightly acidic reaction.

At home Prickly spruces grow in rocky and sandy soils. Therefore, when preparing the soil mixture, it is necessary to add sand, high-moor peat to the excavated soil, the earth from the coniferous forest will not interfere. In too poor soil, you can add no more than half a bucket of leaf humus. When planting Blue Spruce, manure and nitrogen fertilizer are excluded.

Planting hole should be dug at least 2 weeks before planting, prepare a garter stake. If a seedling in a container is chosen for growing Blue Spruce in the country house , the pit should be twice as deep and as wide as the earthen clod. For a large size, the depth and width of the pit exceeds the size of an earthen clod by 25-30 cm.


Planting of Blue Spruce in the plot

On the farms, young seedlings are grown in plastic containers, thanks to which Blue Spruce is planted from spring to autumn . If it is decided to plant a large tree from the nursery, the work is carried out from October to April (except for the period of severe frosts), when the tree does not vegetate.

Mix the soil removed from the pit with additives. Pour drainage (crushed stone, expanded clay, broken brick) at the bottom with a thickness of 20-30 cm. Drive in a garter stake. Pour part of the prepared earth mixture into the pit, install a lump with a seedling, fill in the rest of the earth and compact so that the soil from the container and the soil of the site are on the same level.

Planting of spruce is completed by tying the plant to the stake and abundant watering. To regulate soil moisture, its surface in the near-stem circle must be mulched or sown with lawn grass.

Blue Spruce needs more time to grow in the first few months. So that its roots do not dry out and do not get wet, in the spring it is recommended to pour a little water 5-6 times a day. When the growth of young shoots becomes noticeable, watering can be reduced to two times a day. During the dry season, more water should be given.

Blue spruce care after planting

First 5-7 years Blue spruces grow very slowly. Spring care for Blue Spruce involves a one-time top dressing with a complex mineral fertilizer or a specialized one, for example, Florovit or Green Needle. Organic fertilizer cannot be applied. The nitrogen formed in it stimulates the growth of tissues to the detriment of their density and winter hardiness. When the tree begins to give an increase of 20 cm or more, top dressing should be excluded in the process of caring for the Blue Spruce. If this is not done, then the crown will not be dense enough and fluffy.

In the first years after planting the Blue Spruce in autumn , the branches should be lifted and fixed with a net so that the snow does not break them. In early spring and on sunny winter days, needles can get burned. For such cases, it is recommended to add shading with a fabric or agrotextile to the care of the Blue Spruce. Remove cover in April.

Comprehensive care for Blue Spruce up to 8-10 years old includes sanitary and shaping pruning. First, dried and damaged branches are cut out. Then the elongated young shoots are shortened. Older trees independently form a beautiful crown, they only need sanitary pruning.

Blue spruce care requires regular inspection of the shoots. If pests are found that have changed the color of the needles, galls, it is necessary to cut out the damaged branches, carry out a complex treatment of plants with fungicides or insecticides.

Blue spruce care - tips from Greensad

If you decide to decorate your backyard or country house with such a truly solemn tree, you need to do it according to all the rules and carefully. There are certain rules for planting and growing blue spruce.

First decide on a seedling. For large varieties, a large area of ​​\u200b\u200bthe site and very nutritious soil are needed, only under such conditions will you grow a powerful blue beauty. But for low-growing blue spruce, too fertile soil will not work, it will not allow the crown to form properly, and the tree will stretch too far up. It is undesirable to plant blue spruce in calcareous soils. If there is such a soil on the site, it should be improved - acidified. The acidifying agents may be ammonium nitrate, ammonium chloride or ammonium sulfate. But we must remember that spruce prefers slightly acidic soil, do not overdo it. Do not forget about good drainage, which should be laid at the bottom of the planting hole. Drainage can be the most common: broken brick or rubble. This will prevent the roots from getting wet and rotting during especially rainy periods. But for the superficial root system, drying out is also detrimental.

Trees cannot be planted too close. Blue spruces grow quite quickly. The optimal distance between blue spruce seedlings is 2-3 meters. Blue spruce seedling purchased from a garden center is usually grown in a container. This guarantees a high-quality root system and is the key to survival on your site. And you can plant container seedlings from March to October. The planting hole should be 25 cm deeper and 20 cm wider than the root ball.

Fit Features

Spruce belongs to light-loving plants, so it is advisable to plant in open places, this is necessary for the correct formation of the crown. If the landing was made in a shaded or thickened place, the crown will not be so regular and elegant in shape. Immediately after planting, water the seedling abundantly, and then, throughout the growing season, water the plant once a week. All of course depends on weather conditions and abundance of rainfall. In dry weather, young spruces need not only to be watered, but also to loosen the soil in the root zone, but not deep (5-8 cm). In summer, it is useful to wet blue spruce needles with water from a hose or watering can. It is better to water the plant in the morning or in the evening. Water only with warm water. Warm water dissolves nutrients faster, and they are more intensively absorbed by the roots. Cold water (below +12 C) weakens the vital activity of soil microorganisms and can even damage the absorbing roots of the plant. But excessive watering is undesirable. Water moves nutrients to a depth inaccessible to the roots, in addition, it displaces oxygen from the soil, which makes it difficult for the roots to respire. Of great importance is the operation of retaining moisture after watering, which consists in mulching the near-stem surface. Peat, compost or crushed tree bark is used as mulch.

For the first 5 years, you can feed the tree with mineral fertilizers once a year, in spring, immediately after the ground has thawed. Remember the main rule: never fertilize blue spruce with organic fertilizers.

For the first 5-7 years, pay close attention to the crown of the blue spruce. Perform sanitary pruning: remove dry twigs, damaged and diseased shoots. This should be done in spring and autumn.

Diseases and pests of blue spruce

Unfortunately, with a lot of effort and growing blue spruce, you may encounter diseases and pests. Often, blue spruce is affected by fungal diseases that lead to the fall of the needles or a change in its color. In this case, it is necessary to carry out the treatment with foundationazole twice with an interval of 10 days. Dosage 10 g per 10 liters of water.

Another problem with blue spruce is the formation of rust, i. yellow-brown stripes on the needles or complete yellowing of the needles. In this case, it is necessary to spray with fungicides for 10 days. It is necessary to process not only needles, but also branches and a trunk. If the branches are too infected, they will have to be removed.

Blue spruce can easily lose its attractiveness if it gets pests. Moreover, if more than 75% of the needles are affected, then the tree will die altogether.

  1. Sucking (spruce aphids, hermes, scale insects, mealybugs and spider mites). The needles have acquired a yellow tint, after which they begin to fall off quickly. These symptoms are characteristic of damage to spruce aphids. You can fight this pest either by washing the infected places with soapy water or by partially cutting the needles in those places where the pest colony is located. Sticky white formations appear at the ends of the needles, often the spines take on a curved shape, and bumps (galls) begin to form. All these are signs of damage to blue spruce by Hermes spruce-fir. It will help to remove damaged areas of needles (in particular, cones) and treat blue spruce with a solution of Fufanon or Karbofos. The needles are enveloped in a thin white cobweb, after which it darkens and falls off - this is the result of exposure to the spruce spider mite and its larvae. Spraying with colloidal sulfur or acaricides will help to cope with the pest.
  2. Coniferous (spruce sawfly, moths, butterflies and their caterpillars). The needles of a young tree in the upper and lateral parts change color to red-brown, the buds are eaten. This means that needle-eating pests appeared on the blue spruce. In order to get rid of them, you need to dig up the soil near the trunk, destroy the nests of the larvae, treat the tree with insecticides.

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