What is the best ratio for tree fertilizer?

The foundation of every landscape is vibrant and colorful trees and shrubs. Their natural beauty provides form, structure, and scale to your landscaping, as well as providing welcome shade and ecological benefits.

Apart from adequate sunlight, water, and good quality soil, most plants need that little extra push to thrive. You can give them just that if you know the best fertilizer for trees and shrubs, and when to use it to get the best possible outcome.

We have years of experience trialing and testing various products, seeking out the best tree fertilizers available today. So let’s get straight to the detail of what the market has to offer.

Best Tree Fertilizers

If you’re in a hurry and just want to know the best tree fertilizer for your garden then here’s a summary of the products that I recommend you try. They are all excellent tree fertilizers and I was very pleased with their performance in my backyard.

Convenient pre-measured fertilizer spikes, designed to be pushed one inch into the ground for a slow-release feed throughout the season.

Choosing the Best Tree and Shrub Fertilizer

Like all plants, trees and shrubs require a variety of nutrients to thrive, including nitrogen, potassium, and phosphorus, as well as a blend of micronutrients, such as calcium and boron. A lack of key nutrients will cause stunted growth in stems, leaves, and roots, and leave your plants susceptible to pests and disease.

Before applying fertilizer to your garden or plants, you should take the time to test your soil with a soil pH tester kit, or a nutrient test kit, in order to determine which nutrients your shrubs may be lacking, and the condition of the soil’s pH.

Nutrient Balance N-P-K

The acronym N-P-K is a way of describing the nutrient composition of a fertilizer. Each letter is an abbreviation of a nutrient, where N stands for Nitrogen, P for Phosphorus, and K for Potassium. For example, the packaging may tell us that a certain product has an N-P-K 6-6-6 fertilizer, it would contain 6% Nitrogen, 6% Phosphorus, and 6% Potassium. But what are these numbers and what do they do?

(N) Nitrogen is what the plant uses for foliage or leafy growth. This is typical of any of the vegetative growth stages of a plant.

(P) Phosphorus is important for root development and the production of fruits and seeds.

(K) Potassium is primarily used in the production of flowers and fruits, so great for tomatoes or other high blooming species like roses.

So if we follow this idea through we can look at how two very different fertilizers could be used on different types of Trees.

This Arborvitae is a fast-growing leafy evergreen. There’s no need to look for a purpose-made arborvitae fertilizer. But you would need to look out for a high Nitrogen product to feed the hungry fast leafy growth.

This tree does not produce showy flowers, but you often get attractive cones or buds on these evergreens so some form of Phosphorus and Potassium will be required. Arborvitae Fertilizing with an N-P-K of 13-3-4 would work well in this example.

On the opposite side of the spectrum, a shrub like this Hydrangea has a huge showy bloom. So it stands to reason that this plant will need a high ratio of Potassium.

But we also need to pay attention to the vegetative qualities of this plant, so Nitrogen and Phosphorus are still required.

A good hydrangea fertilizer N-P-K would be something like 8-4-12, offering good Nitrogen balance for foliage and high Potassium for beautiful flowers.

Soil pH

Soil pH refers to the level of alkaline or acid within the soil. All soils have a natural pH level based on the composition of the minerals within the soil in that geographic location. The pH growing range of plants is typically somewhere between 5.5-7.5 pH with each species having an optimum range within that. There are always outliers and some species thrive outside of this typical range, as low as 4.5 and as high as 8.0.

pH is important for many reasons, but the primary concern of gardening enthusiasts is simply to understand how the pH level of soil directly affects the availability of nutrients to plants. Or in other words, plants feed better at their preferred pH level.

Quick or Slow Release Tree Fertilizer

Tree and shrub Fertilizers can be either slow-release or quick-release compounds. This basically refers to the speed at which the tree fertilizer breaks down into the soil and dissipates its macro and micronutrients to the plant.

The rate at which tree food is released into the ground, and then absorbed by your trees, can be controlled. The fertilizer ‘form’ plays an important part in how it dissolves and gets released into the surrounding soil. Powders dissolve fast, whereas granules or spikes break down slowly. Fast and slow-release products both have their purpose.

Slow Release Tree Fertilizer Spikes

Young trees generally benefit from slow-release fertilizers, as they provide a steady release of food and they are less prone to cause fertilizer burn to tender young tree roots. I really like to use fertilizer spikes, sometimes referred to as fertilizer sticks. They offer a pre-measured and controlled method to release food over an extended period. This means I can put it down once rather than repeatedly fertilizing, and avoid fertilizer burn.

Spikes will often provide too large a load when fertilizing shrubs, so in this case, look towards a powder or granular product.

Quick Release Tree Fertilizer

Quick-release tree fertilizers work better on established mature trees that need a quick boost of nutrients. If your tree looks tired, yellow, or lackluster, a quick-release formula will probably be best. Typically a quick-release powder or granular formula can be applied as a top dressing or by drilling or digging holes and filling them with tree food. In some cases liquid feed is useful, but this really should be used regularly, as in fortnightly, or when a really quick dose of nutrients is required.

To decide on the best tree fertilizer for your plants, consider why you’re feeding it, your shrub or tree’s growth stage, and how you want to deliver the nutrients it needs.

Chemical or Natural Tree Fertilizer

There are two main types of fertilizers you can find on the market: organic and mineral. Mineral fertilizers are chemically processed and supply plants with adequate quantities of essential nutrients. Whereas organic fertilizers are made from natural sources, such as manure and plant residue, which provide less precise quantities of nutrients but are made from naturally occurring materials that do not undergo chemical processing.

These fertilizers can be in the form of liquid, granular, or spikes, again depending on how you wish to deliver the feed to your trees or shrubs.   

Organic Tree Fertilizers

Organic tree fertilizers come from animal and plant materials. They work by slowly releasing the nutrients and are gentle on the tree’s roots. The downside is they take longer to yield effective results. The best ingredients for organic fertilizers include bone meal, manure, and crushed shells. Read the product’s label to check the ingredients and the quantity to use. It’s not unusual for organic fertilizers to smell…, well, natural. In some instances, this may attract unwanted attention from wildlife.

Inorganic or mineral Tree fertilizers

They are typically nitrogen-based compounds that contain sodium nitrate and ammonium sulfate. An all-purpose inorganic fertilizer will have a complete ratio of N-P-K mixture, which makes an excellent choice for malnourished trees and shrubs. The upside is the N-P-K can be controlled with a great degree of accuracy during the manufacturing process. Therefore, yielding excellent results. The downside is they are chemically derived.

Now that you have a basic understanding of different fertilizers for trees and shrubs, it’s time to share our shortlist of the best fertilizers for trees and shrubs.

9 Best Fertilizers for Trees and Shrubs

When it comes to tree fertilization, no single formula or compound is perfect for every situation. Some people want to use a general fertilizer that they can use on trees, and plants, indoors, and outdoors. Whilst other gardeners require a very specific product for a single purpose, such as purely for citrus trees or evergreens. With this in mind, we have selected what we believe is a broad variety of excellent products for you to use when fertilizing your shrubs and trees at home.

Our search criteria include the quality of the fertilizer compounds, its overall performance for its intended use, the level of customer satisfaction taken from thousands of customer reviews across all major retail platforms, and the product’s ease of use. All of this combined with our experts’ many years of experience, has enabled us to provide our shortlist of the best tree and shrub fertilizers.

Pros

• Easy to use and great for foliage
• Best value for money product
• Ideal for long-term tree and shrub care
• Excellent oak tree fertilizer and other deciduous trees

Cons

• Spikes need to be kept dry once the packet opened

This slow-release fertilizer from Jobe’s contains easy-to-use tree fertilizer spikes. The shape of the spikes is what makes them so easy to apply as all you have to do is insert them into the ground where needed and cover them with soil. Jobe’s Tree spikes are one of my favorite fertilizer products, including this standard version, the spike for citrus fruit, or evergreen tree fertilizer spikes. They have served me very well.

Since the spikes work as a slow-release feed, it makes them ideal for newly planted and young trees. If applied at the beginning of the season (early spring), the spikes will last all the way to the end of the growing season, eliminating any waste, and saving you money and time.  

The pre-measured fertilizer sticks have an N-P-K 15-3-3 suitable for beautiful leafy foliage. Perfect for deciduous trees and shrubs making it a great oak tree fertilizer, as well as an excellent product for dogwood, elm, birch, maple, and poplar to name a few more. Making it the best fertilizer for trees and shrubs. Check out Jobes Tree Spike’s latest price on Amazon.com.

How to use: water the soil thoroughly before application. Place the appropriate number of spikes along the tree’s drip line, (for every two inches of trunk diameter, use two spikes). For shrubs, use one stick for every 3 feet of height.

Customer Reviews: Across all forums and retail outlet customer reviews, this product has impressed. With just how easy it is to apply in these convenient spikes. Picking up an average user score of 4.6/5.

Pros

• Delivers outstanding results
• Organic and one of our favorite products

Cons

• Digging is required during application for the best results

Espoma Tree-Tone Tree Fertilizer is a long-lasting slow-release organic plant food that contains bio-tone microbes. It’s 100% natural and organic and delivers outstanding results with its N-P-K 6-3-2 formulation.

For best results, I like to use this product twice a year in the standard spring and fall windows. It’s not as easy to apply, requiring some digging, but the results are excellent. This is a good all-rounder because it is formulated for use as an apple, pear, and cherry tree fertilizer as well for use with chestnut, walnut, willow, and cypress trees.

Despite the additional work required to apply this product it still comes right at the top of the list, as the second-best fertilizer for trees and shrubs. Available to buy online here.

How to use: For smaller trees or shrubs simply sprinkle the product over the ground equal to the root spread. This can be estimated by matching the diameter of the branch spread. For large trees make drill holes around the drip line of the tree, approximately 3-6″ deep and 2-3″ in diameter, and fill with fertilizer. Water thoroughly.

Customer Reviews: Despite its more specialist nature this tree fertilizer has gained a loyal following and customers gave this product an incredible 4.7/5 based on performance. Probably the best product on the market, despite the extra work required to apply. An excellent fertilizer for fruit trees.

Pros

• An excellent choice for flowering trees, as well as a fertilizer for palms, and ferns
• An easy apply a slow-release fertilizer
• Great for use indoor and outdoor

Cons

The Miracle-Gro Shake ‘N Feed tree and shrub fertilizer is a slow-release tree and shrub food for all types of plants, flowers, trees, and shrubs. What I love about this star product is the fact that you can conveniently use it on both indoor and outdoor plants and as you can tell by its name is super easy to use. Just shake it onto the soil and rake it in. Perfect for trees and shrubs, but also a great all-around fertilizer.

With its excellent formula of long-lasting, all-purpose plant food, your trees and shrubs will enjoy all the nutrients they need at the beginning of the growing season for up to 3 months. Its relatively high levels of potassium mean this is a great product for flowering and fruiting trees and shrubs. I use it as a fertilizer for blueberry bushes.

The slow-release formula can be used to help the root and stem strength of the shrubs, with natural ingredients such as earthworm castings, feather meal, and kelp to keep plants and trees thriving all year round. Producing luscious greed foliage and colorful flower blooms. This is one of our top picks for general tree and shrub use. You can buy this fertilizer online here.

How to use: simply mix the granules with the topsoil for in-ground or container use, then water thoroughly. Alternatively, simply rake the tree fertilizer into the topsoil ahead of any forecast rainy weather.

Customer Reviews: Over 4,000 satisfied reviews from customers who have seen excellent results awarding this product 4.6/5.

Pros

• Will bring browning evergreens back to a strong green foliage
• Easy to use and great value
• The best fertilizer for pine trees

Cons

• Spikes need to be kept dry once the packet opened

As part of the same product range as the Jobe’s Tree And Shrub Fertilizer Spikes work in exactly the same way. A slow-release 4″ fertilizer spike that is perfect for spring and fall applications. This product range is available in packs of 5, 9, 15, and 150 spikes. A pack of 15 should be enough to feed 3 trees for a whole season. Check the latest prices here.

With an N-P-K of 13-3-4, making these spikes are a perfect pine tree fertilizer and the perfect choice for firs, spruce, cypress, holly, western cedar juniper, and acid-loving ornamental evergreens. This formula is slightly lighter and tailored more towards evergreen feeding requirements. But could be used with success on all non-flowering trees and shrubs.

How to use: water the soil before application. Hammer or push the required number of spikes along the tree’s drip line, (for every two inches of trunk diameter, use two spikes). For evergreens use one stick for every 3 feet of height.

Customer Reviews: Just like the standard tree and shrub fertilizer spikes from Jobe’s, we see great customer feedback for the specialist evergreen tree fertilizer spikes. Scoring 4.6/5. Making it the best fertilizer for evergreens.

Pros

• Super easy to apply
• Ultra-slow release fertilizer
• Great for trees and shrubs in containers

Cons

• Not suitable for large garden trees

Okay, not a specialist tree fertilizer but without a doubt one of the most popular general-purpose fertilizers on the market with excellent results. Osmocote Plus slow-release formula is a high-quality product that incorporates a very clever design. A small linseed ball outer shell (often mistaken for plastic) that houses a 15-9-12 nutrient mix. The whole linseed ball is then coated with a slow dissolving coating to provide Osmocotes slow-release technology.

The fertilizer can effectively feed for a whole season with its 6 months of slow release. This product is not suited to large garden trees, but it is very good for trees and shrubs in containers or pots, including indoor plants and ferns, so well deserving of inclusion in our list. This is the second general-purpose fertilizer on our shortlist and it brings a whole load of benefits for those of you looking for convenience and excellent performance for smaller species of trees and shrubs.

How to use: Sprinkle 1 scoop of fertilizer per 4 square foot of planting area and mix or dig into topsoil and water in. Apply once every 6 months. Simple!

Customer Reviews: Amongst the tens of thousands of customer reviews across all major retailers and forums this multi-purpose fertilizer scores an impressive 4.7/5. You can buy this fertilizer online here.

Pros

• Suitable for a wide range of plants
• Very easy to use, just sprinkle on the ground

Cons

A slow-release evergreen fertilizer that helps trees and shrubs grow well, is Scotts Evergreen and Flowering Tree Fertilizer. It has an N-P-K of 11-7-7. We like this product’s easy application, just sprinkle it onto the soil and rake it in. Once the fertilizer is released into the soil, it will continue feeding for up to 2 months.

One minor letdown is the lack of iron which helps prevent the yellowing of leaves. But apart from that, flowering trees, evergreens, acid-loving plants, and flowers will love this fertilizer. In fact, it’s so safe to use that the chances of burning your tree or shrubs are near zero, so long as you follow the directions on the package. Talking of packaging, you can buy this product online and receive it packaged in a practical resealable bag.

How to use: 1 cup per 35 sq feet. Apply every 2 months starting from early spring. The fertilizer can be applied directly from the bag to the soil. Apply evenly and water the plant after application.  

Customer Reviews: Thousands of happy customers use Scotts Evergreen and Flowering Tree fertilizer with great results. A really impressive online score of 4.6/5 across all major retail platforms and gardening forums. a re-sealable bag.

Pros

• Reasonably priced product from a premium brand
• Quick results and easy to apply
• Natural ingredients

Cons

• Only suitable for mature trees.

We couldn’t write a shortlist of the best tree fertilizers without including the best-selling Tree and Shrub Food Spikes from Miracle-Gro. This product comes in 12-spike packs and contains only natural ingredients. Each spike is approximately 4″ in length.

You only need to feed your trees evergreens and shrubs once in spring and once in fall using these convenient spikes to see great results. We have used them with great results, there’s no doubting why Miracle-Gro has such a well-established brand name in the industry. A customer-friendly choice Miracle-Gro online here.

How to use: place the enclosed cap on top of the pre-measured solid spike. Insert 2 spikes 2 feet away from the center of the tree’s drip line. Each spike should be at least 3 feet apart. Don’t forget to remove the cap afterward for future use. The spikes should be at least 2 inches below the surface. If the ground is hard use a rubber or wooden mallet to tap the spike into the soil.

Customer Reviews: Over 8,000 users rated this product from Miracle-Gro 4.5/5. Reporting substantial growth after using the spikes. The simple application of this type of product clearly appeals to customers looking for convenience and an easy-to-use product.

Some customers complained of damage to young trees. These spikes are potent and should only be used on mature trees, not in pots or juvenile trees and shrubs.

Pros

• Packed full of natural quality organic ingredients
• Gentle enough to use directly on young tree roots

Cons

• Natural ingredients will smell slightly

Down to Earth Tree and Shrub Fertilizer is formulated for general tree maintenance and for use when planting bare root or container planted trees.

Made with a base blend of bone, soybean, and feather meal with supplemented rock phosphate, kelp, and basalt. It’s a good complex blend of natural ingredients that is kind to your garden. The slight downside of this blend tends to be the smell, which can attract some unwanted wildlife.

How to use: The best way to apply this tree fertilizer during planting is to simply mix 1-3 cups of fertilizer into the backfill soil. This natural compound is delicate and will not burn young trees or shrubs’ roots. For existing trees either dig in or pour into holes drilled 3-6″ deep around the tree drop line to avoid a run-off.

Check Down To Earth’s latest price here

Customer Reviews: Down to Earth is a lesser-known brand, but appeals to the eco-minded gardener and homesteaders. We have been a fan of their products for some time and would highly recommend their product to anyone looking to be organic. Scores 4.5/5.

Pros

• Unique 2-in-1 insecticide and fertilizer
• Offers 12-month pest control protection

Cons

• Not a substitute for a high-quality fertilizer
• Only suitable for mature trees

BioAdvanced Tree and Shrub Protect and Feed is a unique slow-release fertilizer with a blended insecticide. The fertilizer is an N-P-K of 2-1-1, so not the most effective on the list but still worth a mention given its dual function as a pest control formula.

This product will help control whitefly, caterpillars, may beetles and leaf miners, and many more garden pests for up to 12 months with one application. This product is useful for mature trees with less demanding nutritional needs, that are also prone to attack from pests. It’s available to buy on Amazon.com.

How to Use: Available as a granular compound or concentrate. Apply 1/4 cup of concentrate for every 1″ circumference around the tree trunk, or 3/4 cup for every one foot of shrub height. Simply sprinkle the granules around the base of the tree or water in the concentrate around the plant’s roots.

How to Fertilize Trees and Shrubs? 

When considering how to fertilize trees and shrubs, the objective is to put the nutrients where they can be best absorbed by the plant’s roots. So, it is important to feed the entire root system of the tree. As you are probably aware, roots normally extend beyond the outer parts of the branches. Think of the root system as being a mirror image of the tree branches. Therefore the fertilizer should be distributed above the roots for maximum effect. 

The simplest and most effective fertilizing method is to spread the granular fertilizer evenly over the entire root zone or place a spike 2 feet away from the tree, or for larger trees to arrange spikes at regular intervals around the tree.

To determine how much fertilizer your trees and shrubs require, you can calculate the amount of nitrogen per square foot of root spread. For example, trees and shrubs can receive up to 4 pounds of nitrogen-rich fertilizer per 1,000 sq feet of root spread every year. The younger the plants, the higher rate of nitrogen is required. But in truth, any credible manufacturer will provide simple and easy-to-follow dosage instructions on their packaging.

Pro-Tip

Newly-planted trees

Since these trees are babies, they will only require minimal feeding with a slow-release organic tree fertilizer to avoid root burn.

Note: avoid liquid fertilizers as they have the quickest release rates. Go for granular or other dry forms of tree fertilizers instead. 

Young trees

This is the time when you need to encourage the rapid growth of your young tree by increasing fertilization dosage. Use the recommended amount by following the manufacturer’s instructions. Feeding your young plant twice a year is perfect for encouraging growth. 

Mature trees

Once your trees have matured, their growth rate naturally slows down. This is when you should reduce fertilization applications to once every 3 years as the trees can now stand on their own feet, or trunk, or should that roots! 

When to Fertilize Trees and Shrubs? 

Using appropriate doses of fertilizer is key to maintaining good tree health. Along with water, sunlight, and carbon dioxide, fertilizers are required to provide shrubs with macro and micronutrients. However, before you start showering the soil with fertilizer, it’s best to determine the best time to feed your shrubs. After all, appropriate timing is critical to promote flowering and stimulating healthy foliage.   

Fertilizing in spring

Late April is perhaps the best time to fertilize trees and shrubs. This is when the tree and shrub fertilizer has the best chance to influence new growth, around one month after the fertilizer application in April. Trees and shrubs require feeding before this new growth starts. To provide an early feed to allow the nitrogen-rich fertilizer to absorb into the new shoots as they grow through the spring and summer and develop into healthy and vibrant shoots.  

Fertilizing in fall

Another excellent time to apply fertilizer is in late fall. This is the time for the plant to grow even more after spring fertilizing. Once the temperatures fall to 40 degrees or lower, apply higher concentrations of the fertilizer to help your shrubs resist freezing. Fertilizing during September or October helps trees and shrubs become hardier by giving them staying power through the colder winter months.

How Often Should You Fertilize Trees and Shrubs? 

How often you should feed your trees and shrubs depends on their age and the season. Young plants often require more fertilizing to get strong. As a general rule of thumb, feed your young shrubs once every two weeks until they mature. This, of course, depends on whether you use an extended-release or slow-release fertilizer. To avoid burning your plants, read the directions of the fertilizer and use it accordingly. 

Once your trees and shrubs have matured, they will generally require fertilizing no more than twice a year, once in spring (April) and once in fall (September or October). As we discussed earlier treating trees during these two periods will help strengthen your plant for the dormant and growing seasons. 

Verdict: Best Fertilizer for Bushes And Trees

So there you go a comprehensive list of the best tree fertilizers available based on our own experience and many hours of research into customer opinion across a wide range of retail platforms and gardening forums.

Just bear in mind different trees and shrubs have different nutritional requirements, so choose the product that will work best for your specific species or base your decision on where your tree is in its lifecycle.

I hope my review of the best fertilizers for trees and shrubs helps you pick the right product for your needs. If you’re still unsure, consider the easy-to-apply and longer-lasting fertilizers that come in the form of fertilizer spikes or Shake ‘N Feed by Miracle-Gro. Or perhaps go for the excellent general-purpose Osmocote Smart-Release, which you can use all around the home and garden for all your growing.