6 Best Fertilizer For Magnolia Trees | How And When To Use

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Jun 19, 2023

The majestic magnolia tree is an old tree that has been around longer than bees, and bees like its healthy pollen and heavenly nectar.

The Magnoliaceae family has hundreds of species, only a small fraction of which are present in populated regions. These may be deciduous or evergreen; their heights can vary from a “dwarf” 8 feet to a substantial 70 feet.

The finest fertilizer for magnolia trees will be vital to maintaining their lush foliage and the huge, multi-hued, and fragrant blossoms they’re renowned for.

Best Fertilizers for Magnolia Trees

Read to the bottom for suggestions on how to fertilize these vintage bloomers. However, if you’re only searching for the top fertilizer for magnolias, here are my top three recommendations, which I’ve tested in various temperatures and soil types.

Selecting the Best Fertilizer for Magnolias

The unique nutritional requirements of magnolias must be satisfied to promote a profusion of big, fragrant flowers. Although not known as heavy feeders, these trees thrive in healthy, nitrogen-rich soil.

Before receiving nitrogen from the soil, magnolias awaken from their winter slumber. This is why I use a pre-flowering 4-8-4 fertilizer with a high phosphorus content for cultivars that bloom in the spring. After flowering, turn to a typical tree and shrub fertilizer such as 16-8-16. If you use a typical 10-10-10 top dressing, it will still function.

It has been found that fertilizing magnolias of any species should be done gradually and consistently to ensure that all this seasonal beauty grows in a healthy, unforced manner. Apply a standard top dressing from early spring to early summer instead of a slow-release fertilizer in the spring.

Pro tip: Although nitrogen is more important than other macronutrients, your soil will need less if it is fruitful. An evenly balanced feed (10 NPK) would be more suitable.

Understanding N-P-K Ratio

Knowing what your trees require, as established by a good soil test, makes it simple to choose the appropriate NPK. The answers to these will select a proper ratio of nutrients to add to what your soil currently provides. But what precisely is an NPK?

For instance, an 18-6-12 NPK has 18% nitrogen, 6% phosphorus, and 12% potassium. These macronutrients are essential for the healthiest plants. To support diverse environmental circumstances, such as soil quality, different NPK ratios are created.

To produce chlorophyll, which promotes green color, and plant food production via photosynthesis, nitrogen (N) is a crucial component.

The mineral phosphorus (P) is essential for tree development and general structure. We are encouraging strong root growth and quickening tree maturity.

The movement of water, minerals, and carbohydrates throughout plants, shrubs, and trees is facilitated by potassium (K).

Nutrient Uptake and pH of Magnolia Soil

In general, different tree species need different soil pH levels. Many of them can tolerate soils between alkaline and somewhat acidic.

Particularly in an acidic pH range between 5.0 and 6.0, magnolias thrive. Testing the pH in the area surrounding your magnolia could be beneficial, mainly if your tree exhibits symptoms of malnutrition, stress, or a lack of blossoms.

Nutrient mobility increases as the pH of the soil falls below 5.0. They become too accessible and take up more energy than your tree requires. Roots cannot access soil nutrients when the pH exceeds 6.0 because they are locked in place. Inevitably, this problem causes nutritional deficits and limited development.

Granular Vs. Liquid Fertilizer

The ideal fertilizer for magnolia trees is often slow-releasing, granular fertilizers rather than liquid alternatives.

Granules progressively degrade with the assistance of soil bacteria, sufficient moisture, and soil temperature. They are giving magnolia trees the type of regular, constant access to nutrients that they need. Depending on the brand, they often accomplish so with only one application for the growing season.

If you live in a short-growing season, you understand the necessity for speedy fulfillment. However, significant amounts of liquid nutrients are often absorbed immediately and quickly. Due to this spike, inadvertent overfertilization is regrettably fairly prevalent and may result in irreversible harm to magnolia trees.

Despite this, liquid fertilizers do offer advantages. Liquids provide a fast absorption of nutrients for speedier root development and the emergence of new growth when young magnolia trees are planted in less-than-fertile soil.

Even if you often use slow-release fertilizers, giving your plants a rapid dose of some liquid nutrients might be helpful during significant growth spurts, to compensate for any shortfalls, or during dry spells.

Spray or liquid concentrate?

Concentrated, pre-mixed, and water-soluble granular types of liquid fertilizers are available. When used as a soil drench or in slow-drip irrigation systems, they provide nutrients directly to the plant’s roots. Liquids may quickly alleviate chlorosis (yellowing leaves) as a foliar spray.

Using liquid feeds might be more cost-effective and lead to quicker outcomes. However, they may only sometimes be more effective in the long run than slow-release alternatives.

Overfeeding is one of the most frequent reasons for tree failure, as was already established. This is true, particularly with liquids, and may result in root and leaf burn. Therefore, strictly using products responsibly and according to the manufacturer’s instructions are advised.

Both organic and synthetic granular fertilizers are simple to apply and can provide ongoing nutrition for up to nine months. Each granule releases nutrients when its covering progressively dissolves due to increasing temperatures and moisture in the soil.

Granular Options

The progressive supply of nutrients to plant roots is their main advantage, instead of dumping a ton of heavy nutrients on them at once when they don’t need it.

Applying granules involves uniformly spreading them around the base of trees, shrubs, and other plants. They don’t need moisture to grow and are less likely to contaminate neighboring surfaces or groundwater.

Fertilizer Spikes

Spikes are a helpful tool to have if you have a lot of potted plants. They come pre-measured in various sizes, are simple to press into loamy soil, and pose no danger of burning.

It might be challenging to put spikes since the soil surrounding older magnolias tends to get compacted. Points have the advantage of being broken up and distributed uniformly around big trees. The same easy nutrient flow is provided.

Increased soil moisture and soil microorganisms cause nutrients to be released from spikes, which also has the advantage of enhancing pest and disease resistance. Then, leftovers may be kept without creating a mess.

Comparison between Organic and Synthetic

The choice between organic and inorganic fertilizers for your magnolia comes down to taste and desired results. However, having a thorough grasp of each and how it impacts your surroundings might help you make a wise choice.

Organic foods are made from plants or animals and have nutritional levels similar to those accessible to trees in the environment. These choices provide optimum aeration and drainage while boosting soil fertility and nourishing trees for longer.

Minerals and chemical compounds are used to manufacture synthetic fertilizers in large quantities. By delivering more significant amounts of nutrients than plants would typically get access to, they may significantly increase the development of branches and buds. However, they have little to no effect on the soil’s long-term fertility or its healthy microbial activity.

Reviews of the Top Magnolia Tree Fertilizer

In areas with warm summers and moderate winters, magnolias thrive. However, smaller kinds may be potted and overwintered inside in colder climates.

A variety of magnolias surrounds my yardhance to try out several fertilizer choices. Based on NPK results, ease of use, and product characteristics that can work with most soil types, my selections for the top 6 performers are the following.

1. Down to Earth Organic Flower Fertilizer Mix 4-8-4


  • Works well with all blooming trees and plants.
  • Designed for solid growth, stunning flowers, and robust plant stock.


  • With its organic scent, it could draw in animals and pets.

With Down to Earth Flower Fertilizer, you’re in good hands if you seek something wholly organic. Your Magnolia will benefit from the enhanced phosphorus in this NPK as it emerges from its winter hibernation and prepares to blossom.

Since nutrients are more quickly absorbed in potted plants, I decided to try this solution on my collection of potted dwarf magnolias. Within a few days, fresh buds emerged, and the leaf shoots started to change to a more prosperous, glossy green. Additionally, I saw that blossoms stayed longer.

For new seedlings, use 1 to 2 cups each hole, mix them into the soil, and water in the well. Side-dress older trees once a month during the growth season with 1/4 to 1/2 cup per plant.

2. Jacks Classic 20-20-20 All-Purpose Fertilizer


  • Optimum nutrients for the growth of buds and green leaves.
  • Compared to other top brands, it dissolves quicker and cakes less.


  • It could emit an earthy smell.

I often use these water-soluble Jack’s Classic granules to aid in the establishment of newly planted ground-grown magnolias, particularly in less-than-ideal soil.

After planting a few seedlings, I experimented with this as a foliar spray and a soil drench. A few weeks later, robust root development had started. As seen by the plant’s more numerous than anticipated blossoms and its brilliant, emerald-green, and copper-colored foliage.

Regarding practical feeding applications in and around the garden, the adaptability of Jacks Classic has no limitations. It may be used as a fertilizer for potted plants, vegetables, trees, shrubs, and border plantings. When anything requires quick nutrition at any point throughout the growing season, it has become my “go-to” solution.

Apply one spoonful for every gallon of water used. Every 10 to 14 days, repeat.

3. Shake ‘N Feed Trees and Shrubs 18-6-12


  • In only two days, new leaves and buds will develop.
  • Formulated to raise the soil’s pH for plants that prefer balance or acid.


  • If not watered in thoroughly, it results in root and leaf burn.

I like to test Miracle-Gro to see how it compares to the competitors. I shook this feed with a nitrogen concentration of my mature Magnolia, which I knew had a pH problem in the soil.

New flower buds and the brown foliage’s transition to green occurred within a week. Thanks to the pH adjustment, my lovely Magnolia could now absorb nutrients more.

This may be used to feed older magnolia trees, which often need more nitrogen, and to maintain the leaves healthy and free of pests after blooming.

Use: Shake the necessary quantity into the soil within the drip line of bushes planted in the ground. Work up to 2 tbsp into the soil in pots. After application, carefully rinse both.

4. Dr. Earth Organic 4 Acid Fertilizer 4-5-4


  • For healthy soil, it contains proprietary probiotics.
  • OMRI organic certification.


  • When used as a tea, it could be seductive to animals and people alike.

Thanks to safe products for both humans and animals, I’m much more comfortable allowing my children and canines to play in areas I’ve fertilized. In terms of application, this is comparable to Miracle-Gro’s Shake and Feed. But all-natural, with seven distinct types of benevolent bacteria.

On two distinct magnolia trees, I put this to the test. I have strewn dry grains around one in the drip line. Then, I brewed tea from the granules and immersed it in the soil. My canine “helpers” were drawn to the earthy fragrance, but both gave me the same fantastic foliage and bud development.

Use as directed on the label by scattering or incorporating the prescribed quantity into the soil—granulated water in the well. The amount needed to successfully cultivate a plant depends on its species, its size, and its container.

5. Scotts Flowering Tree Continuous Release Food 11-7-7


  • NPK mild enough for soil with good composting.
  • Rapid expansion in a single season.


  • For trees in poor soil, the NPK ratio could be too low.

I have several potted Babydoll Magnolias growing in well-composted soil, and they responded exceptionally well to this slow-releasing, granular alternative from Scott’s. I am reducing my worry that too much nitrogen would cause root burn.

The number of flowers on my dogwood and hydrangeas also rose due to the excellent phosphate and potassium ratio. Win-win!

Applying 1 cup to each square foot of the growing area inside the drip line will provide food for up to two months. After entirely watering, work the granules into the top 3″ of the soil.

6. Espoma Organic Holly-Tone 4-3-4


  • Specifically designed to improve fruit and flower harvests.
  • Greater pH for plants that prefer acid.


  • If sprayed on mulched soil, a greater dosage could be necessary.

This Holly-Tone blend, an alternative to Dr. Earth granules, also includes beneficial microorganisms and a well-balanced NPK. This 4-3-4 mix has it all, including additional sulfur to balance the pH of your soil.

In addition, it is intended to help individuals become more tolerant of cold temperatures. Since magnolias typically thrive in warmer regions, this undoubtedly gives gardeners an advantage further north.

Use 1 cup per foot of spread-out branch on shrubs. 1 kilogram per inch of diameter for tree trunks. Once in the spring and then half as often in the autumn.

How to Feed Magnolia Trees

Because they are light feeders, magnolias benefit best from a progressive fertilizer strategy. A constant supply of nutrients will be delivered to mature trees if you use a slow-release fertilizer.

A faster-acting liquid that promotes rapid growth and root establishment may initially benefit seedlings needing more feeding.

However, excessive amounts may lead to forced growth and brittle branches susceptible to pests, illness, and frost damage. When given the freedom to develop naturally, magnolia trees often grow in shape and color more healthily.

Fertilizers with a more excellent nitrogen content and generous levels of the micronutrients phosphorus and potassium will promote abundant blooms, brilliant foliage, and strong tree structures.

Naturally, the directions may vary depending on the brand. However, the suggested application rate for granules is 1/10 pound per inch of tree trunk diameter. Application of these just before a predicted downpour can speed up activation.

To avoid burning, liquid fertilizers should be administered using a watering can or hose connection during the more excellent parts of the day.

Keeping Burn from Fertilizer

The overapplication of fertilizer is the main reason for fertilizer burn. Soil testing is necessary to see if your Magnolia genuinely requires it. To ensure you’re applying the correct quantity, also measure the trunk.

Remember that too much liquid nitrogen applied to the soil or sprayed over foliage will burn the roots. Too much potassium and phosphorus may cause the ground to become too salty, rapidly absorbing any moisture present and causing your trees to become dehydrated.

The following are signs of overfertilization:

  • A growing crust on the top of the dirt
  • Withering or yellowing of leaves and branches
  • Leaf and bud decrease during the off-season

There are measures you can take to attempt to revive your Magnolia if the disease is detected early. Cut off any branches or leaves that are withering or decaying. To remove extra fertilizer, thoroughly water the area where you previously applied it. Mulch should then be placed over the root zone to absorb moisture.

When Should Magnolias Be Fertilized?

As they emerge from winter slumber in the spring, magnolia trees develop quickly, often producing blooms before they leave. Growth somewhat slows down after foliage appears. Apply your fertilizer before or just as new buds form along the stems for the best results.

Apply a second dosage, if necessary, to your Magnolia by mid-July. Fertilizers that release slowly require time to work. Any after-fertilization will encourage new growth that an early frost might harm, leaving the tree susceptible.

Fertilizer shouldn’t be used a second time if it is under stress from the summer drought. Lack of water may damage roots, causing them to burn or go into survival mode. When it lacks the vitality to do so, sending forth new growth and blossoms.

In time, the condition of the soil will play a role. Splitting the treatments has worked well for magnolias grown in sandy soil—A pair of times in the early and late spring.

Magnolia Tree Pre-Blooming Fertilization

By fertilizing your Magnolia tree in early spring, just as the blossoms are beginning to expand, you can direct a proportional amount of its energy toward its natural tendency to produce abundant flowers before the foliage. The balance will favor luxuriant vegetation.

At this time, providing good irrigation is equally crucial. Water enhances the tree’s ability to absorb and distribute nutrients. Bud’s output will also be aided by more sunshine. When selecting a planting location, keep this in mind.

Testing the soil to see which nutrients were lost during the previous year is a good idea before fertilizing. The outcome will allow you to modify your application to account for any inadequacies made apparent.

A lack of blooms, however, may only sometimes signal a problem. While some wait until they are at least ten years old, other magnolia kinds don’t bloom until they are three.

How often should I fertilize a magnolia tree?

The brand you choose, the soil’s quality, and the age and size of your tree will determine how often you should fertilize your magnolia trees. However, since most fertilizers are designed to work with various plant species, be sure the NPK satisfies your Magnolia’s nutritional requirements.

In rich soil, trees may not need any at all. However, the ground may soon run out of nutrients when trees starve.

When buds appear in the spring, mature trees will require their first application of slow-release fertilizer. The organic granules from Dr. Earth need to be applied again in 6 weeks. The shake and feed option from Miracle-Gro lasts for up to three months.

Jack’s Classic triple 20 and Down to Earth’s organic flower mix quickly give worn-out trees what they need to regain their vibrant vitality in nutrient-deficient soil.


The results are in! The soil quality and age of the tree will majorly impact the best fertilizer for magnolias. Before blossoming, magnolias need increased phosphate and potassium; thus, Down to Earth Organic Fertilizer is the ideal choice at the beginning of spring.

Jack Classic All-Purpose Fertilizer can assist correct nutritional deficits and promoting robust, healthy growth from your Magnolias for new plants and areas where soil fertility is a problem.

Magnolias require Miracle-Gro Shake N’ Feed after blossoming if you want them to survive the remainder of the summer. To promote healthy foliage and resilience to pests and diseases, work this into the soil to boost nitrogen and potassium availability.

Espoma’s Holly-Tone granules help promote nutrient and moisture circulation if extra potassium is required, increasing your chances of a successful bloom.


The key to lush, healthy magnolia trees with vibrant green foliage lies in the judicious use of the best magnolia tree fertilizers. Always remember to fertilize magnolia trees appropriately considering their unique needs, while opting for organic fertilizers can enhance the overall soil health and the robustness of your magnolia plants. Among the options we have discussed, you can make a suitable choice depending on whether your magnolia plant is a southern magnolia, a magnolia grandiflora, or another type among the family of magnolia trees magnolias.

Consider using continuous release plant food, especially for potted trees, to ensure an optimal nutrient supply throughout the growing period. Additionally, take extra care to shrub protect your delicate plants from harsh conditions. In the end, it’s about cultivating an environment that allows your magnolia trees to flourish and adorn your garden with their exquisite beauty. With the right care and fertilization strategy, your magnolia trees will be the envy of the neighborhood.

Therefore, a comprehensive understanding of the nutritional needs of your magnolia plants and the correct use of the best magnolia tree fertilizers is a must for gardeners aiming for stunning results. Keep your garden full of life, color, and magnificent magnolias by staying informed and choosing the right fertilizer for your specific needs.

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