Yellowing blue spruce needles - Ask Extension
Can you advise if my spruce has an insect or disease problem. The needles are yellowing at the base. Picture attached.
Knowledgebase
Yellowing blue spruce needles #925092
Asked February 26, 2026, 12:10 PM EST
Can you advise if my spruce has an insect or disease problem. The needles are yellowing at the base. Picture attached.
Boulder County Colorado
Expert Response
Hello Anna,
Thank you for contacting CSU Extension with your question about yellowing on the tips of your blue spruce needles.
It's very difficult to make a diagnosis from photos, especially disease or insect damage. When did you notice this starting to happen? Are you providing water in the fall and winter? Are the needles turning color in the interior of the tree (not just the outer part of the limbs)? Have you noticed any needle drop, especially on the interior, older growth of the tree? Has this happened in the past? How old is the tree? Are any of the needs browning (soon-to-be-shed needles typically yellow first, then turn a reddish-orange or brown color before dropping off.)
If you can send answers to these questions it will help us determine what may be happening. You might also consider bringing a branch into the office for the horticulturist to take a look. The branch should be about 12 inches long and include both live, healthy needles and damaged needles. The horticulturist will also be able to see if there's any damage to the bark that could be signs of a problem.
If you decide to bring in a sample, the cost is $7 for Boulder County residents, $11 if not in Boulder County. Our office is at the corner of Hover and Nelson Roads at 9595 Nelson Road, directly across from the Boulder County Fairgrounds.
Regards,
Colorado Master Gardener
CSU Extension Boulder County
Thank you for contacting CSU Extension with your question about yellowing on the tips of your blue spruce needles.
It's very difficult to make a diagnosis from photos, especially disease or insect damage. When did you notice this starting to happen? Are you providing water in the fall and winter? Are the needles turning color in the interior of the tree (not just the outer part of the limbs)? Have you noticed any needle drop, especially on the interior, older growth of the tree? Has this happened in the past? How old is the tree? Are any of the needs browning (soon-to-be-shed needles typically yellow first, then turn a reddish-orange or brown color before dropping off.)
If you can send answers to these questions it will help us determine what may be happening. You might also consider bringing a branch into the office for the horticulturist to take a look. The branch should be about 12 inches long and include both live, healthy needles and damaged needles. The horticulturist will also be able to see if there's any damage to the bark that could be signs of a problem.
If you decide to bring in a sample, the cost is $7 for Boulder County residents, $11 if not in Boulder County. Our office is at the corner of Hover and Nelson Roads at 9595 Nelson Road, directly across from the Boulder County Fairgrounds.
Regards,
Colorado Master Gardener
CSU Extension Boulder County
Hello,
Thanks for the quick reply!
I only moved to this house/state in October so I am not sure about the history, but here are some additional comments:
1. I am not providing water in the winter, we turned off the sprinkler system in October (should we be, I thought everything is dormant?)
2. The needles are turning color in the interior of the tree, the newer growth seems to be unaffected. The needles on the top half of the tree are also all green, its just toward the base and more in the interior where you see the yellowing.
3. I do not see any significant browning or needle drop around the tree.
4. I think a small tree may have been put in when the house was built in 2017, but I don't know exactly how old it would be.
Let me know if you have any additional thoughts or if it would be helpful to bring in a branch for a lookover!
Also I do have one other unrelated question related to vegetable gardening, if you can also help! With this warm year is it still good to start seeds at the same time (around the May 10 final frost date?). I assume its better to be safe than sorry, but maybe things like spinach might benefit from going in early depending how late march/early April looks?
Thanks!
Anna
Hi Anna,
Thank you for writing back with more information about your spruce tree. It does appear that this may be a watering issue.
While trees and other woody plants, like shrubs and some perennials, do go dormant in the winter, they still need supplemental water during dry fall and winter periods. Having little to no snow cover to provide soil moisture from October through March can stress and cause damage to root systems, which weakens plants and makes them prone to disease and insect damage.
Below is a link to CSU Extension's fact sheet about watering in the fall and winter: "Fall and Winter Watering of Plants and Trees."
https://extension.colostate.edu/resource/fall-and-winter-watering-of-plants-and-trees
You mentioned your sprinkler system was turned off in October. Sprinkler systems shouldn't be activated in the winter, so that's a good thing. You'll see sprinklers mentioned in the fact sheet, but that's not for winter. The other methods for trees are deep-root fork or needle, soaker hose, or soft spray wand. These methods for watering require using a hose for connection. Do disconnect the hose (or hoses) and drain after use.
Some needle drop is normal in evergreens, including spruce trees, as part of an annual growth cycle. Typically, that process is for soon-to-be-shed needles to turn yellow first, then they turn a reddish-orange or brown color before dropping off. Trees can have varying levels of needle shed, even within the same property or general area.
Needles on the lower portions of the crown or closest to the trunk are most commonly shed because they are older. According to Dr. Dan West of the Colorado State Forest Service, needle drop from spruce trees can occur three to four years after a stressful or drought year. In other words, if what is happening to your spruce tree now is stress from drought and not enough water, it may not shed a lot now but you may see it later.
Monitoring trees for cold weather damage and keeping up with watering should maximize the trees' health and vigor as they come out of dormancy in the spring and summer months.
All that having been said, for your own peace of mind, you may still want to take a sample into the Extension Office.
On to vegetables!
May 10 is the average last frost date, but the date doesn't vary significantly. Still, I always listen carefully to weather information for any anomalies.
Starting seeds varies with the type of plant and even the cultivar. For that reason, it's best to follow the instructions for when to start them indoors. The packets will also tell you if the seeds should not be started indoors; some vegetables, especially root vegetables do better when they're directly sowed into the soil. Some vegetables do better when directly sowed because they don't like their roots disturbed; i.e., moving them from a pot to the soil may keep them from doing as well as if the seed goes from your hand to the soil. Spinach does best when direct sowed.
Soil temperature is one of the best ways to determine when you should plant your starts. The link below is to "CMG GardenNotes #270, Vegetable Planting Guide. It breaks down information by the type of vegetable (cool, warm) and gives the minimum, optimal and maximum soil temperatures for germination and planting.
https://cmg.extension.colostate.edu/Gardennotes/720.pdf
I also recommend that you take a look at the "Colorado Vegetable Guide", an online publication from CSU Extension. It's a pdf, and it's free for you to download and/or print so it's handy when you need it.
It has 85 pages of information about climate, irrigation, soil nutrients, seed starting and more. It also includes a section with information about commonly grown crops in Colorado, including the plant traits and growing information. Insects and disease management are also discussed. The book is free for you to download and/or print.
https://growgive.extension.colostate.edu/wp-content/uploads/sites/63/2021/01/Colorado-Vegetable-Guide-2.1.pdf
I hope all this information is helpful to you. It's on the long side (to say the least!) but it's good to know the "whys and wherefores" of what can happen and why.
If you have any other questions, Anna, please don't hesitate to get in touch with us again.
Regards,
Colorado Master Gardener
CSU Extension Boulder County
Thank you for writing back with more information about your spruce tree. It does appear that this may be a watering issue.
While trees and other woody plants, like shrubs and some perennials, do go dormant in the winter, they still need supplemental water during dry fall and winter periods. Having little to no snow cover to provide soil moisture from October through March can stress and cause damage to root systems, which weakens plants and makes them prone to disease and insect damage.
Below is a link to CSU Extension's fact sheet about watering in the fall and winter: "Fall and Winter Watering of Plants and Trees."
https://extension.colostate.edu/resource/fall-and-winter-watering-of-plants-and-trees
You mentioned your sprinkler system was turned off in October. Sprinkler systems shouldn't be activated in the winter, so that's a good thing. You'll see sprinklers mentioned in the fact sheet, but that's not for winter. The other methods for trees are deep-root fork or needle, soaker hose, or soft spray wand. These methods for watering require using a hose for connection. Do disconnect the hose (or hoses) and drain after use.
Some needle drop is normal in evergreens, including spruce trees, as part of an annual growth cycle. Typically, that process is for soon-to-be-shed needles to turn yellow first, then they turn a reddish-orange or brown color before dropping off. Trees can have varying levels of needle shed, even within the same property or general area.
Needles on the lower portions of the crown or closest to the trunk are most commonly shed because they are older. According to Dr. Dan West of the Colorado State Forest Service, needle drop from spruce trees can occur three to four years after a stressful or drought year. In other words, if what is happening to your spruce tree now is stress from drought and not enough water, it may not shed a lot now but you may see it later.
Monitoring trees for cold weather damage and keeping up with watering should maximize the trees' health and vigor as they come out of dormancy in the spring and summer months.
All that having been said, for your own peace of mind, you may still want to take a sample into the Extension Office.
On to vegetables!
May 10 is the average last frost date, but the date doesn't vary significantly. Still, I always listen carefully to weather information for any anomalies.
Starting seeds varies with the type of plant and even the cultivar. For that reason, it's best to follow the instructions for when to start them indoors. The packets will also tell you if the seeds should not be started indoors; some vegetables, especially root vegetables do better when they're directly sowed into the soil. Some vegetables do better when directly sowed because they don't like their roots disturbed; i.e., moving them from a pot to the soil may keep them from doing as well as if the seed goes from your hand to the soil. Spinach does best when direct sowed.
Soil temperature is one of the best ways to determine when you should plant your starts. The link below is to "CMG GardenNotes #270, Vegetable Planting Guide. It breaks down information by the type of vegetable (cool, warm) and gives the minimum, optimal and maximum soil temperatures for germination and planting.
https://cmg.extension.colostate.edu/Gardennotes/720.pdf
I also recommend that you take a look at the "Colorado Vegetable Guide", an online publication from CSU Extension. It's a pdf, and it's free for you to download and/or print so it's handy when you need it.
It has 85 pages of information about climate, irrigation, soil nutrients, seed starting and more. It also includes a section with information about commonly grown crops in Colorado, including the plant traits and growing information. Insects and disease management are also discussed. The book is free for you to download and/or print.
https://growgive.extension.colostate.edu/wp-content/uploads/sites/63/2021/01/Colorado-Vegetable-Guide-2.1.pdf
I hope all this information is helpful to you. It's on the long side (to say the least!) but it's good to know the "whys and wherefores" of what can happen and why.
If you have any other questions, Anna, please don't hesitate to get in touch with us again.
Regards,
Colorado Master Gardener
CSU Extension Boulder County
