Spruce trees are known for their year-round color, as they are part of the evergreen family of trees. Although these hardy trees typically keep a varying shade of green every season, you may notice some needles beginning to turn red.
Why do spruce trees turn red? The important thing to note is that it is not normal for spruce to turn red. Underlying issues such as needle rust, pests, or blight are often behind unexpected color changes.
If you notice this color change, even if it’s only on a few needles, it’s important to investigate and solve the problem as soon as possible. The faster you start fixing it, the easier it is to prevent the issue from affecting the rest of your tree.
Determining The Cause Of Red Needles On Spruce Trees
Before you can truly know how to fix the discoloration on your spruce tree, you need to figure out why your tree is beginning to turn red. A good place to start looking is in the area where you notice discoloration, and ask yourself three questions:
- Is it exclusively on the tips of the needles?
- Does it spread throughout an entire branch?
- Is the red color primarily on areas that get the most sun, or does it show equally in the shaded areas?
If it’s turning red, your spruce tree may be ill, have damage that you haven’t yet noticed, suffer from a pest infestation, or it could even be lacking essential nutrients that it uses to keep its needles healthy and green.
Additionally, reddening can also just be a product of improper care, such as underwatering or overfertilizing. For more information on what your spruce needs in terms of fertilization, check out our article on the 5 best spruce tree fertilizers.
Where Is The Redness On Your Spruce?
Depending on whether it covers a small, select area, or seems to spread throughout the tree can tell you a lot about the cause of the red needles.
For instance, if the discoloration is limited to areas that get the majority of the sun, you can easily assume that a likely cause is excessive heat and too little water.
If this is the case, you can also check the soil around your tree. If it’s also very dry or even cracking, you need to improve your irrigation.
For more information check out our article on how to water your spruce tree.
1. Needle Cast Can Make Your Spruce Turn Red
Needle Cast isn’t necessarily a disease in the way that we would think of human ailments. However, it is a serious condition that needs to be treated as soon as it’s detected.
Signs Of Needle Cast
- Discolored needles (specifically, brown to red hues, purplish-red or brown, or some yellowing)
- Needles that drop after changing color
- Appearance in especially humid, moderately warm weather
Note: Not all afflictions that cause discoloration cause needles to fall from the tree. However, it is a key symptom of needle cast disease.
What Causes Needle Cast On Spruce Trees?
First and foremost, you need to understand that a needle cast is actually a fungus The fungus in question is often Rhizosphaera Kalkhoffii.
Don’t worry. There’s not a whole lot you can do to prevent it if you’re experiencing very humid weather and temperatures between 65 to 75 degrees Fahrenheit.
With that said, those are the perfect conditions for these fungal spores to really set in, so keep an eye on your trees if that weather lasts for a while.
2. Spruce Needle Rust Can Make Your Spruce Tree Red
Spruce needle rust is another fairly common cause of spruce trees turning a reddish tone (although many times it looks like a light red, or even almost pink, or a tan-brown color). Now, this is another fungus, not the typical disease we talk about.
The other thing to know about spruce needle rust is that the colors progress over the space of a couple of months. In the beginning, some of the needles have bits that look orangish-white on them (or pieces that seem to come from off the leaves). This is typical of the first month or so when the fungus begins taking hold.
Signs Of Spruce Needle Rust
- Needles with bits of light orangish-white on them
- Changing colors as the fungus progresses
- Needles that eventually turn hues of tan, red, brown or pink
- Needles begin to fall off the tree after the last color change
- Typically begins developing in spring when the weather is humid and wet, and not yet too hot
3. Spider Mites Can Make Your Spruce Tree Red
Spider mites are fairly well known to gardeners to attack other, smaller species of plants. However, that doesn’t mean larger species, such as spruce trees, are invulnerable.
In fact, spider mites can be a reason that your spruce tree is turning red or brown.
Spider Mites Are Really Small
Unfortunately, as you may be able to determine from their name, spider mites are exceptionally small.
It’s extremely common for spider mites to go entirely unnoticed until an infestation is well underway, and nearly out of control.
Spider Mites Make Ultra-Fine Webs
A tell-tale sign of spider mites is their ultra-fine webs. These have a somewhat similar appearance to regular spiderwebs, although they’re even finer and smaller. These are even harder to spot when you’re dealing with a large, bushy tree.
However, you can tell when your tree is beginning to suffer from these pests if you spot the damage. You can often spot the beginning signs of damage around the trunk of the spruce, or among the lower branches. You’ll also notice some needles taking on a yellow-brown color.
If you’re familiar with regular spider mites, there’s a difference between those and the ones that are attracted to spruce trees. Spruce spider mites tend to take hold during spring, whereas those that plague the rest of your garden will come when the weather really heats up.
4. Certain Pine Beetles May Cause Redness On Your Spruce
Now, there are plenty of different kinds of pine beetles, and they’re often just as eager to infest a spruce tree as they are any other needle-bearing evergreen tree.
White pine beetles are fairly well known for damaging spruce trees and turning their needles a rusty, reddish-brown color. However, early signs of pine beetles can be seen through the gradual yellowing of needles, and evidence of beetles boring into the tree bark itself.
You may see physical holes in the bark, sap bubbling from holes in the tree, or even granules and dust from beetles digging into the wood.
5. Tussock Moths May Be Why Your Spruce Tree Is Red
Pine beetles may be a burden to deal with, and spider mites certainly are no walk in the park. However, those aren’t the only pests you need to keep an eye out for on your spruce trees.
So, if your spruce trees are turning red or brown, and it doesn’t seem to be because of the aforementioned pests, it just might be tussock moths.
The good news is that if you’re in a more rural area, tussock moths are significantly less likely to damage your spruce trees. However, in areas with a higher population, like cities, tussock moths seem to have the advantage.
Tussock Moths Are Attracted To Blue Spruces
Not only that, but they’re especially attracted to certain species of spruce trees: namely, blue spruces (although Douglas firs are another favorite of these pests).
Blue spruces are already difficult enough to keep blue on their own. Unfortunately, there are some moths and other pests that can prevent your blue spruces from being blue, or even cause them to turn red.
As a caterpillar, they have brown and tan-to-white coloring- often appearing as stripes throughout the body. Another identifying characteristic of the caterpillars is the fuzzy black antennae at the forefront of their heads.
As they grow to moths, they have distinctly dark, charcoal-gray wings with black borders and details.
6. Pine Wilt Can Cause A Red Spruce
Despite its name, pine wilt disease does not affect only pine trees. In fact, it often also affects spruce trees. Nematodes, a type of parasitic worm, are the culprits behind this pesky affliction. And the way trees begin to show damage is somewhat counterintuitive as well.
When we think of worms, we often think of dirt. However, nematodes are a different type of worm. As a result, the damage they inflict on spruce and pine trees actually begins showing at the top of the tree, with browning needles, rather than near the base of the tree.
7. Winter Burn Can Make Your Spruce Tree Red
Spruce trees are well-known as evergreens. Of course, that means that they’re green all year long (more or less). However, one reason your spruce trees might not be green all year is winter burn.
It’s not a literal burn, but rather a condition that can occur as a result of damage to the needles. In particular, it’s damage that occurs during very cold winter months. Note: Winter burn often begins showing at the tops of trees, where the more serious damage starts.
Spruce Trees Need To Be Watered In The Winter Too
Although spruce trees are known to be tolerant of cold weather, that doesn’t mean it’s always an easy season for them. That’s especially true when temperatures are exceptionally low- and even more true when the winds are harsh.
You’re probably used to watering your trees regularly during the summer. What you might not realize is that spruce trees also need to be watered during the winter.
Dehydration, coupled with cold weather and high winds can easily lead to winter burn, which will cause spruce needles to turn brown.
8. White Pine Weevils May Make Your Spruce Red
Despite their name, white pine weevils can actually damage spruce trees, although Norway spruces are one of their favorites.
The good news is these pests usually attach to trees in higher elevations.
These pests feed on the bark and move to mate, after which, they dig holes into the bark to lay their eggs. If you see spots of sap or resin along your tree’s bark, there’s a chance that’s a result of white pine weevils feeding on your tree.
Another tell-tale sign of a white pine weevil infestation is affected branches that begin to droop, and turn light brown giving them a hook-like appearance. You’ll typically see this curve beginning later in springtime, and they will soon fall off the tree.
How To Treat Spruce Trees Turning Red Or Brown
Before we take a deeper dive into how to treat your spruce tree, it’s important to keep in mind that one cure won’t fix every affliction.
Because the cure is often specific to the cause, it’s important to know why your spruce tree is turning red or brown. Hence, why we’ve included the detailed descriptions above about identifying the cause of your tree’s discoloration.
However, some of the treatments do have different steps, so it’s important to first diagnose the problem, and then take the proper steps to treat it.
With that in mind, we’ll go over treatment options for each reason your spruce tree is turning red. Not only that, we’ll also review ways you can prevent these problems from happening in the future.
If your spruce seems to not jump back – you may need to cut it down, check out our article on why you may need to cut down your spruce tree.
Even though you can’t control the weather, you can still help your spruce tree avoid the damage of winter burn.
It’s important to remember- one of the main causes of winter burn is dehydration.
You can check the soil to assess how dry or moist it is. If the soil is obviously dry, it’s definitely time to water the tree. But don’t worry, preparing the soil before winter can also help retain moisture. The best way to preserve moisture in the soil over winter is by adding mulch.
If you’re looking for a good mulch, we recommend Mighty Pine Mulch.
Because needle cast and spruce needle rust are both afflictions that arise because of a fungus, most of the treatments are the same. For that reason, we’re grouping their treatments together.
The first thing to do is reduce excess moisture on your trees. Basically, if you have irrigation or sprinklers that also spray water onto your tree’s needles, direct them to another part of your yard.
Pruning Your Spruce Can Help
You can also prune your spruce tree to eliminate some branches within the bulk of it.
The goal here is to enable more ventilation (airflow) to the inner branches of your tree. In turn, this extra air will help wick away some moisture, making that part of your tree less susceptible to fungus.
Did you know that pruning can also keep the size of your tree manageable in the long run? Read more about it in our article on 6 simple steps to keeping a blue spruce tree small.
You May Need A Fungicide
While the measures above can help prevent it, if the fungus takes hold, you’ll need to use a fungicide. There are different fungicides you can use.
In the case of spruce needle rust, you can often forego fungicide treatments, unless the needle rust becomes severe.
If either needle cast or spruce needle rust is a recurring problem, you may need to use a preventative fungicide.
Copper-based fungicides are popular for preventing these issues, just like this Southern Ag Liquid Copper Fungicide.
Spider mites are pesky pests, and they’re not easy to get rid of. Unfortunately, there aren’t many options to get rid of them without using a pesticide.
Of course, not all pesticides are created equally. There are certain types you can use, which are more eco-friendly and won’t harm other trees and plants around your spruce.
If an infestation is bad enough that it’s damaging your spruce tree, it needs treatment. Before you spray any pesticides on your tree, always check to make sure they’re not going to harm your tree as they get rid of the pests.
Simply giving your tree a good spray with water beforehand will help the efficacy. This helps dislodge some of the pests, which gives the treatment a head start.
Tussock moths, much like spider mites, are best done away with by using a pesticide. However, they are easier to spot, which means prevention can be a key factor in keeping your spruce trees healthy.
You probably won’t know you have a tussock moth problem until your spruce tree suffers damage. And even after you treat your trees, you’ll want to keep an eye out for cocoons and tussock moth caterpillars the next time spring comes around.
If you do notice some cocoons, carefully remove them, and treat your tree again, if it’s within the acceptable time frame (some treatments should only be used every few months, so check the instructions).
In some cases, there are sprays that actually deter these pests for up to 12 months. If you’re looking for a low-maintenance solution that lasts, try BioAdvanced Tree and Shrub Protector.
Dealing With Pine Wilt On Your Spruce
Pine wilt disease is perhaps the most serious of all the afflictions we’ve covered. Unfortunately, because the nematodes spread very quickly, there’s not much you can do. Not only do they spread throughout the tree, but they also spread to surrounding trees.
Before you take drastic steps, you need to verify that your spruce tree does, in fact, have pine wilt disease. Why do you need to be absolutely sure? Because it’s commonly known that the only kind of solution is getting rid of the infested tree.
Unfortunately, if you leave the tree as it is, it will only allow the disease to spread to other plants and trees.
While these are different pests, they have a lot of the same habits. As a result, you’ll need to treat them in similar ways. When you treat for white pine beetles and white pine weevils, prevention is key.
Adults typically nest over the winter and then mate and brood around the tree, allowing their offspring to take over the trees in the next spring. Because of that, you need to spray trees in the spring, or you can choose a more holistic pesticide and apply it during the fall.
You typically only need to spray the main branches, or ‘leaders,’ which will help get rid of the larvae that like to hide in there. However, you don’t have to rely on only chemical methods. You can also carefully prune away branches where the pests have burrowed within.
As soon as you see your spruce tree turning red or brown, you need to diagnose the issue. Finding the cause behind the discoloration is crucial.
Whether it’s winter burn, a fungus, or a pest infestation, you need to know what it is in order to properly treat it. Once you’ve treated the issue, do everything you can to prevent it from coming back.
Burke, M. J., Gusta, L. V., Quamme, H. A., Weiser, C. J., & Li, P. H. (1976). Freezing and injury in plants. Annual Review of plant physiology, 27(1), 507-528.
Fischl, G., Csöndes, I., Kadlicsko, S., & Józsa, A. (2008). Study on the factors provoking the reddening and decline of blue spruce (Picea pungens Engelm.). Növényvédelem, 44(8), 401-402.
Heiniger, U., & Schmid, M. (1989). Association of Tiarosporella parca with needle reddening and needle cast in Norway spruce. European journal of forest pathology, 19(3), 144-150.
Lewis, K. J., & Lindgren, B. S. (2002). Relationship between spruce beetle and tomentosus root disease: two natural disturbance agents of spruce. Canadian Journal of Forest Research, 32(1), 31-37.
Whitney, R. D. (1962). Studies in forest pathology: XXIV. Polyporus tomentosus Fr. as a major factor in stand-opening disease of white spruce. Canadian Journal of Botany, 40(12), 1631-1658.
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