Everyone loves a spruce tree. Yep! Those large, blue-painted evergreens you see in all of your favorite mountain towns. They’re pointed, tall, and attractive, and they stay that way all the way through winter when other trees lose their charm and color.
Picea pungens, commonly known as Colorado blue spruce trees, are robust and hardy trees that love high altitudes, direct sunlight, and cold weather. They can withstand some of the harshest weather conditions you’ll find in the United States.
Still, things can also get hard for them under certain conditions, so they need support. But how?
Under harsh and variable or even severely hot weather conditions, plants need extra nutrients to keep them functioning well, so you may need to introduce more nitrogen, phosphorus, and potassium into the soil around your spruce from time to time.
Alright, easy enough. But one of the most common questions we get is, “What is the best fertilizer for Colorado blue spruce trees?”
Well, the short and simple answer would be to use a fertilizer that is high in nitrogen, but that answer isn’t completely sufficient without some supporting information.
So, whether you’re growing your spruce trees for some backyard shade, as privacy screens, or as the perfect Christmas tree for the coming holiday season, don’t waste your time with trial and error.
Follow our complete guide to choosing and using the very best fertilizers for spruce trees.
Growing Conditions for Blue Spruce Trees
Growing evergreen trees in your garden can be exciting. Spruce trees are a perfect fit for cooler climates and are easy to maintain in areas with harsh and unpredictable weather.
But before providing the best care possible for your Colorado spruce, you should learn a bit more about the ideal conditions for these trees.
Acidic Soil
Soil pH plays a huge role in the health and nutrition of Spruce trees. A lower soil pH level coincides with increased acidity and makes the soil more favorable for the trees, so using high-nitrogen fertilizers is one of the best ways to keep the soil acidic.
It’s a good idea to check the soil pH and soil acidity around your evergreen trees annually. Based on the results of your testing (which can be done at home with some pretty simple equipment), you can use specific fertilizers to help alter those conditions and create the ideal growing environment.
Spruce trees also naturally make the soil around them slightly more acidic because they consistently drop their pine needles, which are acidic themselves. This is why we advise having your soil tested (or testing the soil yourself) annually to determine the right amount of fertilizer needed.
While phosphorus-rich fertilizers will also help reduce your soil pH, the effects are far less than those from a nitrogen-rich fertilizer or other nitrate-based products.
Potassium, on the other hand, has little to no impact on soil pH, so don’t go dumping a bunch of random nutrients around the base of your tree.
Cooler Climates
It probably doesn’t come as a surprise that cold weather conditions are favorable for the growth and productivity of spruce trees.
The extreme heat and dry weather, as you’ll typically find in the dry, arid regions of the US, are relatively unfavorable for most spruce varieties – which is especially true for Colorado Blue Spruce.
Most often, you’ll find blue spruce growing in the Northern regions of the US (or other high-altitude environments).
Direct Sunlight
To keep spruce trees growing efficiently, you need to be sure that they are getting plenty of direct sunlight. These hours will change slightly based on the season, but typically, you should try to mimic the spruce’s natural environment closely.
One reason blue spruce do so well in mountain environments is that they are much higher in altitude and have more direct exposure to sunlight.
Another reason is that the mountains provide all sorts of minerals that have been in the ground for hundreds and thousands of years, which continue to be transported by running rainwater and glacier melt.
To mimic their natural conditions (as much as possible) at home, grow your blue spruce trees in areas with at least a few hours of bright, direct sunlight every day. Regular watering will be vital, and you should aim to water heavily every week or more.
This shouldn’t be difficult. Just be sure not to plant your trees in the entirely shaded areas of your backyard. Even partial shade can be stressful, so exposure to the sun will be key for a healthy tree, especially in those dark and dreary midwestern and northeastern winters.
What is the Best Spruce Tree Fertilizer?
High-nitrogen, slow-release fertilizers are always the best choice for your Blue Spruce trees. Just be sure that you are not creating too much of an acidic soil medium by over-applying fertilizers.
Your best bet is to have your soil pH tested every few years. The right conditions in your soil are the key to success with spruce trees, which is also why slow-release fertilizers are the ideal choice for spruce trees since over-acidification can halt or alter growth patterns in most plants and trees.
You can buy an at-home soil pH tester at most gardening outlets, and you can consult us here at Potted Exotics, or talk to a local nursery to decide how much fertilizer to apply throughout the growing season.
What Is High Nitrogen Fertilizer?
Most high-nitrogen fertilizers are organic-based fertilizers that include urea. Urea (also called carbamide) is a 100% organic compound that has two amino groups and a carbonyl functional group. Basically, urea is an organic waste product of living organisms and is the primary compound in human urine.
While we don’t necessarily recommend taking your next bathroom break next to your beautiful blue spruce, these organic compounds are some of the most beneficial to spruce trees in terms of fertilizer.
Since high-nitrogen fertilizers are typically lower (at least by ratio) in phosphorus and potassium, the fertilizer acts fast and combines well with the native soil to make it favorable for spruce trees.
About NPK
NPK is the nutrient ratio between nitrogen (N), phosphorus (P), and potassium (K). These nutrients are essential for every living organism, especially plants, and are the most commonly considered fertilizer base for most trees and plants.
Since we know that the need for Nitrogen is stronger for spruce species than it is for many other plants, high-nitrogen fertilizers do wonders for these trees. A typical high-nitrogen fertilizer has an NPK ratio of 10-6-4, 12-6-4, or 10-8-6, but the NPK ratio should reflect the current soil conditions around your spruce.
To make this clear, if a bag of fertilizer has an NPK ratio of 10-6-4, that would indicate that it contains 10% nitrogen, 6% phosphorus, and 4% potassium.
The higher amount of Nitrogen makes the fertilizer more reactive and effective in reducing the soil pH.
In combination with hydrogen in the air, NPK fertilizer produces more absorbent urea. It helps to seep fertilizers deep into the root ball and root system of trees and plants.
What is Urea Fertilizer?
Urea fertilizer is one of the most common spruce tree fertilizers around – particularly for those just looking to boost soil nitrogen and create a more acidic soil environment. It has a whopping 46% nitrogen content!
The NPK ratio of urea fertilizer is 46-0-0. An absolute beast when it comes to taking the alkaline out of the ground. Also, since spruce trees have little use for phosphorus, why waste the materials and money on including it in your application?
Urea fertilizer is super reactive and works for outstanding absorption to bring out results worthy of the spruce tree’s growth.
Urea Fertilizer and Soil Acidity
One thing to understand is that while urea reacts to make the soil more acidic, it only makes the soil slightly more net-acidic and has a similar acidifying effectiveness as anhydrous ammonia.
The reason urea makes the soil more acidic is due to the chemical reaction that the nitrogen undergoes once applied. And it’s a multiple-step process.
How Does Urea Increase Soil Acidity?
- Once in the ground, urea reacts with water and free hydrogen ions to form both ammonium bicarbonate and ammonium nitrogen. This process is called ammonification.
- The ammonification process is then followed by a process called Nitrification. While some of the ammonium formed in the above reaction will be absorbed by plant roots, the rest will be converted to nitrate through the following reactions.
- Since the number of free hydrogen ions in the soil increases after all reactions take place, the overall effect on the soil is increased acidity (lower pH).
How to Choose the Right Type of Fertilizer for Your Spruce Tree
Choosing the right fertilizer for the healthy growth of your spruce tree is essential. You can find many fertilizers to work for the tree, but choosing the most favorable one for your tree can be a challenge.
Liquid Fertilizer vs. Granular Fertilizers
If you are working with young plants that are delicate and low in height, you can opt to use a liquid fertilizer, as the soil surface should be smooth and will keep the fertilizer from running off the top and make for better absorption. Liqu
However, if you are applying fertilizer to a sloped landscape, the liquid fertilizer will naturally flow downwards, leaving the upper side of the soil with fewer nutrients. In this case, spreading slow-release granular fertilizers is a good choice.
Granular fertilizers will typically stay in place in the soil better, gradually being absorbed by the earth and infusing with the root system.
Remember, the choice depends on the kind of soil and surface, along with the plant’s height and stage.
Organic Fertilizer vs. Synthetic Fertilizers
Another big fight comes here in the form of organic matter fertilizers and synthetic fertilizers.
While overfertilization is becoming more of an apparent environmental problem – particularly in agriculturally-heavy regions – synthetic fertilizers are easy to acquire and use and provide high-quality results.
The good news is that you can make organic fertilizers yourself at home.
You can also buy natural and organic fertilizers from your local garden center, and many producers are refining their products with high-quality organic materials.
Apply organic fertilizers near the base of the tree, as you would with fertilizer spikes, liquids, or granular fertilizers.
What Happens if My Evergreen Tree Doesn’t Get Enough Fertilizer?
Without the right amount of fertilizer, your spruce tree could suffer.
At first, you will observe foliage color, dullness, and then a completely dried tree. The loss of nutrients will damage their productivity and defense line as well.
An insufficient amount of fertilizer makes different types of trees vulnerable to threats like various pests, bugs, and diseases, so you could end up paying a high price for remaining unaware.
Fertilizer not only helps your tree to grow well and sustain its beauty, but it also provides strength. It also enables the tree to fight against pests and other threats sufficiently. However, a newly planted bare-root tree should not be fertilized heavily.
Some fertilizers are good enough to protect your tree from damage and hazards, but the right application rate will optimize results. You can even apply horticultural oils or chemical control to fight off the pests.
You can find more details about fertilizing your evergreen trees in this study.
How to Apply Evergreen Fertilizer?
Other than selecting the right fertilizer, you need to work on its application. It’s not a random spray you apply on the tree or soil. Instead, there is a pretty strict process you should follow.
- Dig the holes around 8 to 12 inches deep in the soil.
- Keep them around 2 feet apart, making a circle against the tree.
- Keep the distance of the circle around a young plant to 1.5 feet, while mature trees can do with about 3 feet.
- Mix up the fertilizer according to prescribed measurements, fill each hole, and let it seep in.
- For the granules, you can sprinkle the granule at the base of the tree and let it sit there in the soil.
- If you use the fertilizer spikes, follow the instructions mentioned on the packaging.
Best Fertilizer for Blue Spruce Trees (Our Top 11 Choices)
| Product | Best For | Usage |
| Miracle Gro’N Shake Feed | All vegetables, roses, trees | Every 3 months |
| Scotts continuously release Fertilizer | Shrubs, Trees | Every 2 months during the growing season |
| Jobe’s Evergreen Fertilizer Spikes | Shrubs, Trees | Early Spring and Late fall, Twice a year |
| Tree help Premium | Trees | After 6 months/Twice a year |
| Fertilome Tree Food | Shrubs, Trees | Early Spring and late Summer, Twice a year |
| Compost Tea | Trees | Every 4 months |
| Miracle-Gro Fertilizer | Flowers, Vegetables, Houseplants, Roses, Shrubs, Trees | Every 7-14 days during active growth |
| Nelson NutriStar Tree Food | Shrubs, Trees | Early Spring and Early Fall, Twice a year |
| Osmocote Smart Release Fertilizer | Shrubs, Trees, and Plants | Every 4 months year-round |
| Golden Tree Plant Food | Shrubs, Trees | 1 to 3 times a week in every new growth season |
| Arbor Green Pro | Shrubs, Trees | After 6 months/Twice a year |
1. Miracle Gro’N Shake Feed
Miracle-Gro Shake’N Feed is a great option to provide a loaded organic feed to your soil for pine trees. It not only spikes growth but also nourishes the soil. Fertilizer enables the soil to make tree roots healthy and their color bright. The soil-based microbes in the fertilizer make it perfect even for well-refined soil. It mixes well and gives long-term results.
2. Scotts Continuous Release Fertilizer
Scotts Continuous Release Fertilizer is one of the best in terms of balanced tree nutrients. It ensures that each part of the tree will see the same nutrients with its latest technology. The fertilizer leads the trees to grow and flourish for a long time coming.
3. Jobe’s Evergreen Fertilizer Spikes
Jobe’s Evergreen Fertilizer Spikes are designed for evergreen trees, giving them ultimate nutrition and support for growth. Along with winters, it works on a slow-release formula for summers. It targets the roots of the plant and works for a quick and better infusion for slow-growing trees. This fertilizer helps protect against pests and diseases and provides an ideal amount of nutrients to the tree. The best part of the fertilizer is its pre-measured spikes. You can manage its use according to need.
4. Tree Help Premium
Tree Help Premium High Nitrogen Fertilizer is all set to give your pine trees good energy and protection during growth and sustainability. It lands in the roots and works on the soil to make it rich for the plant and to keep the pests and bugs away. You can enjoy dual benefits with the fertilizer and never have to stress about your tree’s health.
5. Fertilome Tree Food
Fertilome Tree Food Fertilizer is an ideal choice when you want to shoot for less maintenance or fertilizer consumption. Using it twice a year gives your trees enough nutrients and soaks your soil with the best components. Users highly recommend it based on its long-lasting and safer results from frequent fertilization. With a 10-pound bag, you can feed almost five trees at a time.
6. Compost Tea
While looking for some commercial fertilizers, you may be afraid to induce too many chemicals in the soil. If it is heartbreaking for you, then you can use Mighty Plant Compost Tea as an alternative. You can prepare it yourself by brewing the compost. Organic liquid fertilizer is also great for spruce trees and keeps them happy and healthy.
7. Miracle-Gro LiquaFeed Fertilizer
Are you looking for something that can bring your dying trees back to life? Here it is. The Miracle-Grow LiquaFeed Fertilizer is a miracle that lets your trees get all the nutrients they need or crave. Using it twice a year will make your soil rich with the best nutrients and make your trees grow more efficiently.
8. Nelson NutriStar Tree Food
Bringing in a lot of Nitrogen to the soil and increasing the acidity of the soil makes this Fertilizer one of a kind. Nelson NutriStar Tree Food is one of the best players, giving your tree the adequate amount of every nutrient it needs for growth and nourishment. You will be amazed by the perfect growth and blooming effect on your trees.
9. Osmocote Smart Release Fertilizer
Like the other products on the list, the Osmocote Smart Release Fertilizer works on the smart release formula. It helps your trees get balanced nutrients from the roots. It distributes under the surface and in the soil structure to make it good. Not fertilizer, but its price is quite good and reasonable to be used twice a year based on need.
10. Golden Tree Plant Food
Golden Tree Plant Food is a golden food for your Spruce green needles as it boosts the process of photosynthesis in the trees. You can witness amazing growth and lift in your tree’s structure and development. The formula of the fertilizer provides all vital minerals, amino acids, and much more in combination. Using it is quite easy, and you should see optimal results.
11. Arbor Green Pro
Inject Arbor Green Pro fertilizer right into the soil roots of your trees and watch the magic happen. It will travel up to the trunk from the roots, distributing all the nutrients all around the tree. The fertilizer ensures that trees will have an adequate amount of nutrients. Its smart technology always provides the trees with the right amount of nutrients.
Final thoughts
You’ve probably seen pine trees in the rocky mountains absolutely thriving. But, the fact behind this growth is the nutrient-enriched soil. These deciduous trees stand with their roots gripped in the well-drained soil of mountains.
The soil keeps hold of trees and nourishes them well. If you plan them in your garden or private space, you must maintain these pine trees with the best of care. Make appropriate soil decisions to support the roots balls, and plant your new trees at the beginning of the season.
Arrange good drainage at the base of the tree if you have a flat surface, and use fertilizer spikes when possible. It helps you make them grow right and reach the mature height of a young plant. Fertilize your trees in early spring (early summer may be the best time in some locations), ensuring they have a wealth of nutrition to carry through the upcoming growing season.
Be sure to check out the rest of our tree and plant care articles for the most up-to-date and relative information to your needs!