Do you own a blue spruce? If you do, you know how beautiful it is and how excellent it is as an addition to your landscaping. Most people use it as a privacy shield, windbreaker, or border for their yards. You may also see them pop up as Christmas trees.
If your blue spruce tree isn’t blue, it may be the nature of your specific tree. Geographical location, low sunlight, too hot of temperatures, and over-watering can cause your tree to be less blue. The first step to making your blue spruce more blue is to fins out what’s causing it to be less blue.
If you want to find out more, continue on! We will dive deep into each cause, as well as give you suggestions to solve the issues.
A Bit About The Blue Spruce
The blue spruce, also known as the Colorado spruce, scientifically known as picea pungens engelm, is a native evergreen to the west and central Rocky Mountains. It is known for its rich blue-green or blue-gray color and aesthetically pleasing shape.
Landscaping blue spruce trees can grow up to sixty feet tall and become very wide, but in the wild, they can grow up to 75’ tall and 20’ wide!
They can survive in planting zones 2-7 and are very hardy. Landscaping spruces live anywhere from 40-60 years but can grow as old as 150-600 years.
They are best planted during the winter, specifically between November and March, along with evergreens. They have to be planted in winter to establish a strong root system before producing new needles and shoots in the spring.
It is crucial to plant these trees according to their soil, moisture, and temperature requirements. This gives the spruce the best chance of not only surviving but flourishing into a gorgeous addition to your yard.
To learn more about how spruces survive during the winter, head over to our article: Ways That Trees Survive The Winter and How They Do It.
Why Is My Spruce Losing Its Blue Color?
Now we’ll jump in and talk about the change your spruce tree may undergo!
One day, you are admiring your yard when you notice your blue spruce tree is not looking so blue anymore. Its needles have changed into a green or yellow color. Needles have fallen and the branches have become bare.
What an annoyance! What happened to this gorgeous tree of yours?
Unfortunately, blue spruces are prone to a variety of different ailments and environmental circumstances capable of changing the color of their leaves. These can be anything from pests to fungus and vary based on several factors.
Since you can plant these trees in different climates across the country, there is a host of different diseases and environmental factors that can affect the tree and make it lose its rich blue color. Next, we will talk about some of the most common reasons your tree is not blue.
Keep in mind you can prevent and treat some of these ailments, but sometimes they can cause permanent damage and require removal. Luckily, this is not usually the case for blue spruces. Let’s look at the ways your tree might change colors and how to reverse it.
Epicuticular Wax Naturally Affects Blue Spruce Color
Many people assume the Colorado spruce can only be blue when it is healthy, but this is simply not true! Blue spruces can be naturally blue, blue-green, blue-gray, or silver.
This is simply because of the amount of wax coating the needles. This wax, epicuticular wax, coats the cuticle of the leaf.
The wax is important because it determines which wavelength of light is reflected off of the spruce needles. The heavier the wax is on the needles, the bluer it is.
One factor that affects the color of your spruce tree is the condition of the epicuticular wax. Environmental erosion caused by wind, rain, heat, and other types of exposure wears down the wax and causes a different light to be reflected.
This is when you might see a blue spruce tree turn green. As long as there are no signs of pests, disease, or yellowing leaves, then you do not need to worry about the state of your tree. It is naturally occurring and does not affect the health of the tree.
Luckily, epicuticular wax will regenerate, so it should return to its former glory once the growing season has begun!
Geographical Location Affects Blue Spruce Color
According to the University of Massachusetts, spruce trees do best when they are in northern and colder climates. They struggle with hardiness zone 7 because of its higher nighttime temperatures.
Blue spruces struggle in hotter temperatures because any single or combination of heat, humidity, and soil content can affect their ability to grow and produce blue leaves.
In its native climate of the Rocky Mountains, the soil dries quickly, and the temperatures are cooler. Spruces in warmer weather often live in clay-based soils.
Geographical location and climate can also affect blue spruce height. You can learn more about that in our article: 6 Simple Steps To Keeping A Blue Spruce Tree Small.
Blue spruces can handle acidic, dry, rocky, clay, rich, loamy, or sandy soils. They can tolerate drought and flood as long as they are not too severe.
To give your spruce the greatest chance of maintaining its beautiful blue color, plant it in moist soil that is well-drained and fertilized with a pH level of 6.0 to 7.5.
Although spruces are hardy and can handle soil with some clay in it, too much of it causes issues with drainage. Clay soil does not drain moisture very well and your spruce’s roots can become waterlogged. This can lead to root rot and a host of other diseases and pest invasions.
If you’re interested, you can learn more about the best spruce tree fertilizers here: 5 Best Spruce Tree Fertilizers (And How to Use Them)
Insects And Pests Can Cause Blue Spruce Trees To Lose Color
Blue spruces are unfortunately very susceptible to insects, especially if they are in a climate with high humidity. Below are the two of the most common types of insects that you may see invading your blue spruce.
White Pine Weevils
White pine weevils will attack your blue spruce, which can lead to forked or deformed trees, and they can be highly destructive. They can change the beautiful blue color of your tree, but they rarely kill the entire tree.
These weevils attack the tree by feeding on the bark, creating small holes. They lay their eggs in these holes, and after seven days the weevil larvae hatch. The first sign of an infestation is when the holes have resin drops leaking out onto the trunk of the tree.
Once the larvae hatch, they will burrow into the bark of the tree and continue feeding on it. They will destroy the stem, causing the growth from that stem to be halted. The needles on that stem will turn yellow and die.
If you want to keep weevils from attacking your tree, you can use a special insecticide on the main branches of the tree. They are affected in springtime when the weather has been above fifty degrees for at least four weeks.
We recommend contacting a professional because they are the only ones with commercial access to foliar spray. Using a professional is also important because they will know exactly where to spray the insecticide. You can decimate healthy insect populations if spraying on the entire tree and this can cause a host of problems, so leave it to the experts!
Spider mites are another common invader of blue spruces. Spider mites are tiny bugs that thrive off of the chlorophyll in the needles and the fluid of the tree’s tissue. You can see them with the naked eye, but they are very, very small. You will be more likely to see the delicate web that they make over areas of the tree.
One sign of a spider mite infestation is yellow dots on the needles caused by the mite sucking out the chlorophyll.
Eventually, the needle will turn brown and die, but if you can catch the yellow dots before then, then you can confirm it is indeed a spider mite!
Luckily, spider mite infestations are not fatal to your tree. They will cause several needles to dry up and fall off, but not enough to destroy the entire tree.
To get rid of these mites and keep your blue spruce blue, you can do one of two things.
First, you can release mite-eating insects into your tree canopy, like predatory mites, who do not feed on trees and will get rid of the infestation. This is a great natural option that keeps potentially harmful chemicals away from your tree.
Another natural way to keep spider mites from creating too big of a nuisance is to water the tree by using the jet setting on your hose. As you spray into the branches, you will wash away enough spider mites to keep the infestation at a lower level.
Unfortunately, using some insecticidal soaps or oils will cause your spruce to lose its gorgeous blue color, so try the options above before resorting to an insecticide.
Blue Spruce Tree Diseases Affect Color
Many diseases can infect your blue spruce tree, so let’s learn how to identify and treat the most common illnesses of spruces to keep your tree as blue as possible.
Cytospora canker disease is a fungal infection and the most common disease found in blue spruces. Excessive drought, injury, pest-related injury, and a variety of other factors cause them. Spruces in climates with higher humidity are more susceptible to fungal diseases.
The process begins with cankers forming on the tree, recognizable by the white resin that oozes out of it. Although it is a slow process, these cankers can eventually damage your tree by burrowing into it and cutting off nutrients to random branches.
You can tell if your tree has this fungal disease by checking to see if the branches are dying from the bottom up, or if it is dying from the inside out. The needles will turn purplish-brown and begin to fall off.
Although the chance of your spruce dying from this disease is very low, it can still deform your tree and make it an eyesore. The only way to prevent this disease is to apply a fungicide yearly, but it must be done by a certified applicator.
If you notice your tree has been affected, prune away any dead branches, but only during dry seasons. You should also keep your tree properly irrigated and avoid any injuries to the tree, like from a lawnmower or trimmer used near it. As always, contact a professional arborist to ensure your tree gets proper treatment.
Rhizosphaera needle cast is a disease that presents as brown blisters on the leaves of the spruce tree, which change to red and orange over time. Eventually, the leaves form a yellow tissue on the needle, causing an unpleasant color, not the beautiful blue you envision for your spruce.
You can tell if your tree has this illness by inspecting individual needles. The disease is present when you can see small black dots along the shaft of the needle moving away from the blister.
The blisters will eventually grow until the spores burst, infecting surrounding leaves. Wind and rain can also carry the spores to neighboring trees. This means if you have more than one blue spruce on your property, the disease can spread to another one.
You may notice this disease because you are in a drought and have not properly watered your tree. Improper soil quality or sun exposure can also cause this disease.
The best way to prevent this disease is to make sure you provide the most excellent care when planting, fertilizing, and watering. Needle cast loves to prey on trees when there is excessive moisture and humidity, so make sure to plant it somewhere with proper drainage.
What happens when your tree is infected? Unfortunately, there is no cure once the needle has been infected and it will eventually die and fall off.
However, you can eliminate the disease from causing further damage by stopping the spread. Do this by pruning off any dead branches or any branches that you notice are infected.
By doing this, you are removing any spores that would otherwise burst and cause other leaves and trees to be affected. Also, pruning the branches will allow more air into the canopy of the tree, reducing humidity and the chance of this disease attacking your spruce.
Overwatering Dilutes Color From Blue Spruce Trees
Sometimes, your blue spruce is turning brown because it is getting too much water. Just like I said above, climates with higher humidity can cause problems for your blue spruce because it dislikes excessive water.
Too much water will cause your tree to turn brown from the bottom up. You should not be watering your tree more than once a week during dry seasons.
You can tell if your tree is overwatered by feeling the soil around the tree. If the soil is squishy and wet after a week, then it wasn’t absorbed into the tree, and it is being overwatered.
Do your tree’s branches wilt? Do the needles fall off easily, despite their blue color? These are also signs of over-watering.
If you want to slowly water you tree, Greenscapes Tree Bags are perfect for the job. They hold up to 20 gallons of water and gradually release over 6 to 8 hours. Let your tree take in water at its own pace!
If you put too much water into the ground, the roots cannot move oxygen as well as they could, causing a lack of nutrients and ultimately browning leaves.
How Do I Keep My Blue Spruce Tree Blue?
By planting your spruce tree in the right soil and location, you give it the best chance of maintaining its beautiful blue color.
Michigan State University tree experts recommend planting a blue spruce in a spot that receives a lot of sunlight and air movement, as well as soil that has good drainage. They also recommend using a variety of different plant species for your landscaping.
When you use different plant species in your yard, you create a more balanced and healthier ecosystem. The US Forestry Department recommends it because it creates more diversity for your yard, leading to a more stable wildlife population.
This wildlife, like spiders and various insects, is crucial to the health of your tree because they fight off pests that can damage it.
A healthy, pest free tree means a gorgeous color. As a reminder, sometimes a blue spruce will turn green, but this is natural.
Sometimes the wax on individual needles gets rubbed off over time or by weather, causing a change in color. Not to worry, the blue will most likely come back once the next growing season has started!
Most of the time, however, it will stay blue as long as you regularly check it for diseases and infestations. If you catch these early, you can treat the tree and give it the best chance of maintaining the beautiful blue hue.
As always, it is highly recommended to contact a tree professional if you run into any problems with your tree. They will help you keep your spruce stay healthy and blue so you can enjoy its beautiful color for many years to come.
Additionally, you can read our full guide on keeping a blue spruce blue in our article: 6 Simple Steps To Make Your Blue Spruce Tree More Blue.