Conifers are one of the most charismatic plants on earth; they are like cacti among succulents, stand out in character, and graceful beauty. Among them, a special place is occupied by blue spruce. Thick, lush blue-sky needles distinguish this species from other spruces.
My acquaintance with these plants took place as a child, and they were planted in parks and alleys. The unusual appearance amazed and attracted me until I bought my first Colorado spruce.
It was a variety of Hoopsii, and according to many breeders, it has the brightest blue color among all varieties of this species. I completely agree with this, and I also have a variety of Glauca Globosa Blue Spruce, it is also bright but still different from the previous one.
Over the years, I have collected a small collection of these plants. In my garden grow dwarf varieties whose annual growth does not exceed 1 inch. I also have spherical and columnar varieties. I even have a variety of red cones called Hermann Naue. The only thing I failed to get was Weeping Blue Spruce.
I will tell you about all my blue spruces and how I grow them in this article. So let’s start.
Brief Care Information
|Name||Colorado Blue Spruce, Picea pungens|
|Hardiness Zone (USDA)||1-7|
|Light||Sun, Partial Sun|
|Pests||Gall adelgids, Spider mite, Tussock Moth|
|Disease||Rhizosphaera Needle Cast, Cytospora Canker|
|Water||Drought-resistant plant, but loves moist soil.|
|Soil||pH 5.0-7.0, moist, drained|
Buy only quality plants.
In order for the spruce to grow in your garden for many years without any problems, you must choose quality planting material. Many sellers sell improperly grown, low-quality plants with pests and diseases.
There should be no stains or other suspicious signs on the needles. Also, the needles should not be damaged. Insects can intercept between the branches, so be sure to look there to make sure everything is clean. If everything is ok, then we go further.
Remove the spruce from the pot and carefully inspect the roots. The tips should be white with a transition to brown. It should not be rotten. Also, the roots should not contain insects, larvae, or eggs.
The roots should not be strongly entangled in the pot. If the pot already has a large ball of roots and very little soil, it means that the plant is transplanted rarely, and then there may be problems with it.
If everything is ok, you can buy a plant. In the case of online shopping, read what other buyers say about this online store.
A sunny place is best for planting.
Plant blue spruce in a sunny place. Its blue color is formed due to the wax coating. Wax coating, in combination with green needles, gives such a wonderful look to these plants. In this way, the plant is protected from excess sun. If there is not enough sunlight, there will be no wax coating, and the plant will be green.
It is not necessary to plant these plants in a place where the direct sun shines for 12 hours. 6-8 hours of sunlight a day is enough for them. All my blue spruces grow in the sun and look great, some get more sun some less, but overall everything is ok.
If you plant blue spruce in the shade, it will grow poorly. It probably won’t die but as I said above it won’t have a nice blue color. This distinguishes Blue Spruce from Norway Spruce, which can withstand significant shading.
A place in front of the house or the middle of the garden where the blue spruce will be a vertical accent will be perfect for planting. I do not recommend planting these plants close to sidewalks or driveways. Because they, depending on the variety, grow quite quickly and will make it difficult to move through the yard.
There should also be no stagnant water at the landing site.
Plant Blue Spruce in spring or autumn.
Many argue that potted spruce can be planted at any time other than winter. However, I do not agree with this, I used to plant conifers from pots in the summer, and as a result, many of them died. Therefore, I will try to briefly describe everything about the time of planting spruce.
It is best to plant spruces in the first half of spring until they have begun to form new young growth. This time is good because there is no strong sun, and the ground is moist enough.
If all goes well, by summer, the spruce will form enough new roots to survive the hot period. According to my observations, 3-foot-tall spruce in a new location can form 20-inch-long roots in 30-45 days. But this is in the absence of spring frosts and other negative factors.
You can also plant a spruce a little later. However, there is a risk that young shoots may wither from lack of moisture. Therefore, if possible, plant them earlier. I planted these plants when they started to grow after hibernation, in most cases, the plants took root, and everything was fine.
The second auspicious period is autumn, and it can be late summer if you live in the northern United States. The advantages of this time of year are the lack of heat and sufficient humidity. Also, the soil at this time retains summer heat, and in warm soil, the roots are formed very quickly. Here the main thing to plant 30-40 days before the first frosts.
As I mentioned above, I do not recommend planting spruce in the summer, especially in the heat. Although the plants grow in pots when planted in the ground, growing conditions change dramatically, and the plant can get a lot of stress. Add to this the heat and the chances of survival are greatly reduced. Therefore, do not plant blue spruce in the summer.
If, for some reason, you have no time other than summer, then after planting shade, the plant for the entire heat. This can be done with a shading net. Also, water the plant regularly but not with plenty of water.
The second unfavorable period is winter. First, it is almost impossible to dig a hole in the frozen ground. Secondly, even if you manage to plant spruce, then the frost can crush the roots that have not yet established in a new place. This can lead to root rot.
I planted spruces several times in the winter, most of them survived. However, I noticed that they are slightly behind in growth from others.
My recommendation for this chapter is to plant blue spruce in spring or autumn.
The soil should be moist and drained.
In general, blue spruce tolerates a wide range of soils. It can grow in clay or loam, and also feels good in sandy or rocky soil. However, let’s first determine the best substrate for these plants and then talk about other options.
In my opinion, the best soil will be ordinary garden soil or loam mixed with peat. Peat is needed to make the soil lighter; as a result, the plant will grow a little more vigorously. This is especially important in the first years after planting.
Add one-quarter of the peat to three-quarters of the garden soil and mix well. Peat will also make the substrate a little more acidic. It is known that conifers like slightly acidic soils, although they can also grow on alkaline soils.
If you do not have peat, you can add compost, it will also make the soil loose.
Some recommend adding compost to the substrate. I do not recommend doing this because compost can cause root rot. I know that many gardeners successfully use compost, so I will not insist, so you decide.
If you do not have the opportunity to prepare the soil, then you can plant in the usual garden soil that you have in the yard. There is a high probability that the blue spruce will grow normally.
Land with a high sand content (more than 50%) is not very suitable for growing these plants. Blue spruces like moist soil and sand do not retain moisture, so the plants will suffer from drought.
Pure clay is also not the best substrate. Yes, in this type of soil, spruce will also grow, but I recommend adding a little compost. If you do not have such an opportunity, then make at least a good drainage.
When planting, try not to damage the root system.
Suppose you bought a healthy plant, and it’s time to plant it in a permanent place. A few days before that, water the plant well several times to saturate it with moisture. It is necessary to water if there was no rain. This will help the plant to establish itself more easily in the new place, and will also reduce the consequences of transplant shock.
Choose a day when the weather is cloudy or at least so that the sun does not shine too brightly. Avoid planting on sunny days. It is better to choose the morning or evening.
Dig a hole twice the size of the pot in which the spruce grows. Here you need to make a digression; if you have a high level of groundwater in the yard, then you need to make drainage in the planting hole. For drainage, the pit should be three times deeper than the pot. Fill the pit with expanded clay or stones for a third. Then fill it another third of the prepared soil and place the plant there.
The ground level in the pot should be the same as the ground level in the garden. I mean, you shouldn’t dig the trunk into the ground. This is a common mistake for beginners. If you deepen the trunk, then it can rot, and you will lose the plant.
Fill all the free space in the pit with soil and compact it a bit. Do this easily so as not to damage the roots. Then water the plant for the first time, not with plenty of water. Then add a little soil if there is not enough.
Also, after planting, you can water the spruce with liquid fertilizer intended for conifers. This is not a necessary condition, but it will give a little incentive for growth.
Water the plant several times with a small amount of water on the same day when you plant it. In this way, the plant and the soil are better saturated with moisture.
In the first year after planting, keep the soil around the spruce slightly moist. Avoid drying out the root system. During the rooting period, plants are most vulnerable to lack of moisture and excess sun.
Blue spruces love moist soil but can withstand drought.
Ok, let’s talk about watering. As I said, blue spruce after planting needs watering once a week if there is no rain. If the weather is very dry, then watering should be done more often.
1-2 years after the spruce takes root, watering can not be done at all. These plants are drought tolerant and can stay relatively long without water. However, if you want to keep them healthy, I recommend watering them anyway.
In spring and autumn, watering is almost not necessary; at this time of year, moisture is usually enough. The same applies to winter. In winter, the plant sleeps and does not need water.
Watering is needed in the summer if it has not rained for at least ten days, i.e., in drought, they need to be watered three times a month. I rarely water them. In my garden next to the blue spruces grow other plants that need more frequent watering, such as hostas. When dry, I turn on automatic watering, and along with the hostas, the spruces also get water.
From this, we can conclude that if you have an automatic watering in the garden, for example, for the lawn, then there is no need to water blue spruce separately.
A few words I want to say about overwatering, I have never had a problem with this. Even during a very long period of rain, no blue spruce was damaged by excess moisture except for one dwarf variety called Blue Kissen. He lost half of his needles and branches but eventually recovered.
Although I have had almost no problems with overwatering, this does not mean that these plants need to be watered daily. Water them in drought while the soil should be moist but do not need to form a swamp around them.
Feed with fertilizer.
Blue spruces can grow without fertilizers, but if you want them to grow more vigorously and have more lush needles, then they need to be fed. This is especially true for miniature varieties.
I usually use long-acting fertilizers, such as Osmocote. In early spring, I add 0.5-3.5 ounces to each plant depending on its size. This is enough for vigorous growth. I feed spruces once a year.
I noticed that my spruces respond well to fertilization, although the effect does not always become noticeable in the first year.
I want to warn you against overfeeding your plants. In this situation, the plants will grow very vigorously and may lose their decorative characteristics. Also, the branches will become brittle and can be damaged even by the wind. To all, this should be added that overfed spruce will be more vulnerable to disease.
Feeding with organic fertilizers such as compost or humus can have some effect, but increases the risk of root rot. Therefore, I do not recommend using this type of fertilizer. Spruces grow in nature on poor soil and feel great.
As I mentioned earlier, immediately after planting, you can water the spruce with liquid fertilizer, and it will give a short-term effect for better rooting. I also had the experience of spraying the plant with liquid fertilizers. It did not bring much effect, yes, the plants became a little lusher, and that’s it. Therefore, I do not see much point in such fertilizers.
Blue Spruce can be damaged by insects.
Due to their thick needles, blue spruces can become a target for various pests. Some of them can cause serious damage. Let’s take a brief look at the main threats of these plants.
The first most common pest is Gall adelgids. These insects feed on the sap of the plant, and as a result, the branches and needles begin to wither and die.
Signs of the presence of Gall adelgids are deformed growths on the branches called galls. If you notice something like this, it means that you have this pest. The most effective method of controlling it is systemic pesticides. Spray the spruce with a pesticide identified for Gall adelgids several times at one-week intervals.
In most cases, a few sprays will suffice. Also, remove the galls from the spruce.
The second pest is the Spider mite. The problem is that these are very small creatures and difficult to spot. If the needles on one or two spruce branches have started to dry, then take a closer look to see if there are any spider webs. If a spider web is present, then it is a spider mite.
This pest can be controlled only with the help of special pesticides called acaricides. Dilute this remedy in water according to the instructions and spray the plants. Often one spray is not enough, so repeat if necessary.
The third pest is Douglas-Fir Tussock Moth. The larvae of these insects like to eat young needles. If you do not control this pest, it multiplies very quickly. As a result, the plant may be irreparably damaged.
If you notice the caterpillars of these insects, then you should act immediately. There are various ways to control them, but the most effective is the spraying of young needles with pesticides intended against Douglas-Fir Tussock Moth.
There are a few other pests that are less common, but this is a topic for a separate article. In general, I almost never have problems with pests on spruce trees because I regularly spray them with systemic insecticides, which I advise you to do.
Spruce needs preventive treatment against diseases.
Blue spruce, like all plants, can be affected by various fungal diseases. One of the most common is the Cytospora Canker. Outwardly it looks like browning and falling of needles on one or two branches.
However, in reality, it is not the needles but the bark that is affected. Infection occurs through wounds or cracks in the bark. Then the branch under the bark begins to collapse, and as a result, the needles dry up and fall off. The bark itself does not look sick. Infection usually occurs from the lower tier of branches.
This disease most often affects spruces under the age of 15 years.
Unfortunately, there is no cure for this scourge; the methods of control are to avoid infection. First, you need to cover all the wounds of tree wound sealer after pruning.
If you find this disease, prune the affected branches until the disease reaches the main trunk. Treat wounds and disinfect the tool. Burn the branches or take them away from the yard.
The second most common disease is Rhizosphaera Needle Cast. Spores of this fungus overwinter in fallen needles and in spring when the weather is favorable infect young needles. The disease progresses from the bottom of the tree to the top. If you do not act in time, you can lose the tree.
Unlike the previous disease, this will not damage the branches. Therefore, if you find brown needles but the branches are still alive, then it may mean that your tree is infected with Rhizosphaera Needle Cast.
You should plant your plants at a sufficient distance from each other; this will ensure air circulation between them. Air circulation will reduce the risk of infection.
Remove the affected branches and needles. Spray the plants with a fungicide designed to combat this disease. I recommend spraying spruce with various fungicides several times a year for prevention.
By pruning, you can form beautiful garden forms.
Blue spruces do not need pruning, especially when it comes to conical varieties. They grow in fairly correct shape and look great. However, there are cases when it makes sense to prune these plants.
The first is when spruces grow to large sizes and interfere with movement. There are two options. First, you can raise the crown of the plant by cutting a few lower tiers of branches. Second, you can make a ball of spruce by cutting almost all the branches except the 3-4 upper tiers; then, it takes several years to form a spherical shape.
It also happens that the spruce begins to overshadow other plants and takes up a lot of space in the garden. In this case, many gardeners create from their plants garden bonsai called Niwaki. This is quite laborious work and requires a lot of time. It will take several years to form a plant in this style, but the result will be excellent.
There is not as much space in my garden as I would like, so I try to keep my plants compact. I have a Hoopsii Blue Spruce that can grow quite large. Every year I shorten or remove the annual shoots, and the plant remains small. As a result, it becomes thicker, and the needles lusher.
I also have a Glauca Globosa Blue Spruce, it is not quite large, but it needs pruning to give it the right shape. I shape it like a mushroom; it allows me to grow shade-loving plants under it, such as hostas.
When pruning, you should use only sharp quality tools. Disinfect them before and after work. Treat all wounds by pruning sealer. Also, do not prune more than a third of the branches in one season.
The easiest way to multiply Blue Spruce is by seeds or cuttings.
The reproduction of blue spruce is quite a difficult task—the most difficult to propagate rare dwarf varieties. I will quickly tell you about the main ways to help you figure out how to do it.
The first way is to root cuttings. In early spring, before new branches and needles begin to form, you need to cut the annual shoots that formed last year. Choose thick shoots with a maximum number of buds. The more buds, the more energy the cutting will have.
Cut the cuttings with the “foot” with which they are attached to the main branch. Next, prepare a clean soil based on peat. It is best to buy a ready-made substrate for seedlings. Fill the substrate into containers at least 10 inches deep. There should be drainage holes in the bottom of the containers.
Next, clean the lower half of the cuttings from the needles and dip the lower tips (foot) in the rooting gel. Then stick the lower ends into the ground. Water them a little. The soil around should be moist but not wet, keep it that way in the future.
Transfer the containers to a shaded greenhouse. In a few months, the roots should appear. It happens that the cuttings take root in the second year. In general, this is a long and complex process. If 20% of the cuttings take root, then for a beginner, it can be considered a success.
The second method of reproduction is by seed. Unfortunately, in this way, varietal characteristics are not transmitted or transmitted to a very small number of seedlings.
You need to collect the seeds in the fall and dry it well. In the spring, it should be sown in containers as for cuttings, i.e., with clean soil and drainage holes. Then place them in a greenhouse.
In 10-15 days, young plants should appear. They need constant watering and ventilation of the greenhouse. If done correctly, young spruces grow quite quickly and in 2-3 years can reach more than 10 inches in height.
The last way to increase the number of these plants is grafting. This is difficult and, at the same time, exciting process. Only after a few years of practice will you be able to succeed in this. In order for grafting to succeed, you need strong rootstocks and strong cuttings. Also, everything should be done in a greenhouse with high humidity.
Here I will not delve into the grafting process as it is a big topic. I managed to graft spruce several times, and my joy knew no bounds)).
In general, I recommend buying spruce because propagating them is a long and time-consuming process.
Transplanting should be done only in spring or autumn.
From my experience, I can say that spruce is not very tolerant of transplanting. I have not always been able to successfully transplant these plants. There have been several cases where they have died, so I urge you to take it seriously.
The most important thing is when to move these plants. Do this in early spring or late winter when the plant has not yet woken up. At this time, there is no strong sun, and the earth contains enough moisture.
The second suitable time of year is autumn. In autumn, transplant no earlier than October 10-15. At this time, as well as in the spring, there is little sun and a lot of moisture.
Do not transplant spruce in the summer! Most of my attempts to move plants in the summer ended in the loss of the plant. I also do not recommend doing this in winter, because the plant is in hibernation and it does not need additional stress.
For transplanting, it is better to choose a cloudy morning or evening. Before that, water the plant well if there was no rain.
Dig spruce with roots and earth. Do not damage the roots; otherwise, it may not end well. Move the plant to a new location and dig a hole of the same size or slightly larger. Put it there and cover it with the earth, after transplanting, water the plant regularly but with a moderate amount of water. Also, if possible, shade the spruce for several months.