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How to Fertilize Crepe Myrtles & The 7 Best Fertilizers

Explore our top seven crepe myrtle fertilizer picks, and learn proper fertilization processes to enjoy stunning blooms throughout summer.

By
Sean Stratton | Updated January 4, 2023

You need to use an excellent fertilizer to get the best out of your crepe myrtle tree. We’ve compiled a list of our 7 top fertilizers for crepe myrtle.

The Best Fertilizers for Crepe Myrtles

myrtle tree

1. Carl Pool Crepe Myrtle Plant Food

The Carl Pool Crepe Myrtle Plant Food is the best overall fertilizer to promote the healthy growth of crepe myrtles. It is specially formulated with essential minerals and micronutrients to maintain desired growth. The NPK (Nitrogen-Phosphorus-Potassium) ratio is 8-55-7.

The fertilizer is high in phosphorus which will work well to reduce the pH level of soil and make it perfectly acidic, as required for crepe myrtles. This acidity encourages the growth of more blooms, making your crepe myrtle tree more colorful and vibrant.

If your trees have a couple of branches with small brown leaves, you can see amazing results within a week after applying it. This fertilizer will bring back every single branch with more green leaves, a healthy structure, and significant growth.

Pros:

  • Water-soluble fertilizer.
  • Phosphorus for more flowering with vibrant color.
  • Delivers nutrition slowly but works immediately.
  • Helps to ensure better absorption.

Cons:

  • Might be toxic to the aquatic environment in some regions.

Next Read: Top Pumpkin Fertilizers for Larger Pumpkins

2. Nelson Granular Fertilizer for Crape Myrtle & All Flowering Trees

If you want to improve plant health with strong stems, branches, and roots, you should check out this Nelson plant food. This is the best fertilizer for crape myrtles with a blend of nitrogen, phosphate, and potash. It also includes a good range of essential minerals such as iron, zinc, copper, and manganese.

All of these ingredients promote re-growth after pruning, more colorful blooms, and health in all parts of the plant. This product also increases soil nutrients immediately. It will take just a few hours after application to nourish the soil.

This is a must-have for many growers due to its versatile quality. The perfect time to apply this fertilizer is in early spring.

Pros:

  • Professional horticultural fertilizer for crepe myrtles.
  • Five nitrogen sources with different characteristics.
  • Offers long-lasting benefits.
  • Supplies nutrients continuously for up to four months.

Cons:

  • Phosphorus content can be harmful to water quality.

3. Miracle-Gro Shake ‘N Feed for Flowering Trees and Shrubs

When you want to flourish your crepe myrtle with deep green foliage and vibrant blooms throughout the season, Miracle-Gro plant food will provide all the essentials.

It contains many natural ingredients, such as bone meal, feather meal, earthworm castings, and more. This helps to build stronger roots and adds natural microbes to the soil.

This organic element aids in nourishing soil properly from top to bottom. You can apply it to potted and in-ground plants. It supplies food to your plant for up to 3 months. Apply MiracleGro during the first growing season and when planting to help establish the roots.

Pros:

  • Formulated with natural micronutrients.
  • Highly water-soluble plant food.
  • Continuously supplies food for three months.
  • Also works for potted plants.

Cons:

  • Foliage burn can occur.

4. BioAdvanced Tree and Shrub Protect and Fertilizer

If you’re looking for an easy all-in-one solution for your crepe myrtle, look no further than BioAdvanced Tree and Shrub Protect & Feed. It provides 12-month plant nutrition and insect protection with just one application.

It protects your crepe myrtle trees and shrubs from 40+ harmful insects like aphids, Japanese beetles, caterpillars, and more. Plus, it provides slow-release feeding for your plant for up to 1 year.

It protects your crepe myrtles from branch to root and improves overall health and growth. You can apply it to both indoor potted and outdoor plants.

Pros:

  • Specially formulated with 2 in 1 formula.
  • Protects and feeds for up to 12 months.
  • Improves the overall health of shrubs and trees.
  • Apply anywhere indoors and outdoors.

Cons:

  • More expensive.

5. Scotts Evergreen Flowering Tree & Shrub Plant Food

If your crepe myrtle is affected by yellowing foliage, fewer flowers, and weak roots. You need to choose a fertilizer like Scotts Plant Food that will improve green foliage and strong root growth and produce more attractive flowers.

This is a slow-release fertilizer that performs well for crepe myrtles and many other acid-loving trees or shrubs, such as camellias, azaleas, and rhododendrons. It also releases enough nutrients and minerals to develop soil moisture.

It’s pretty easy to use. You can apply it directly to the soil. After every application, watering is necessary. You don’t need to fertilize frequently. It can supply nutrition continuously for up to 2 months. For effective results, apply it before buds are formed in the first growing season.

Pros:

  • Formulated for crepe myrtles and other shrubs.
  • Easy to apply and maintain.
  • Provides long-lasting results.

Cons:

  • Has a strong scent.

6. Purely Organic Tree & Shrub Fertilizer Spikes

Are you searching for a long-lasting, fast-acting organic fertilizer to get more healthy shrubs? This plant food will be one of the best options for you. It’s scientifically approved for organic use by OMRI (Organic Materials Review Institute).

The NPK ratio is 7-0-2, which means it is high in Nitrogen. Nitrogen promotes plant health and growth. It offers nutrition and minerals to the plant roots directly and feeds your plant for up to 3 months.

These spikes are super easy to apply. Put each spike to the ground and use a hammer to drive it in. Apply them in early spring and late fall.

Pros:

  • No chalky dust included.
  • Approved by OMRI
  • Contains rich molasses formula.
  • No bad or strong smell.

Cons:

  • No iron or phosphorus.

Keep Reading: Do Fertilizer Spikes Kill Trees?

7. Espoma Organic Holly-tone 4-3-4 Organic Plant Food

When it comes to growing larger crepe myrtles with superior development and green foliage, Espoma Organic Holly-tone is a great choice. It’s specially formulated for all acid-loving plants like crepe myrtles, strawberries, blueberries, camellias, etc.

It is scientifically approved for organic gardening. It’s a relatively strong and fast-acting fertilizer. You can get more blooms with vibrant colors by applying this. It slowly releases nutrients to your plant as a long-lasting food supply. Apply in early and late spring.

Pros:

  • Rich with natural and organic ingredients.
  • No toxic ingredients, environmentally safe.
  • Particularly formulated for acid-loving trees.
  • Act as a long-lasting food supplier.

Cons:

  • Can damage shallow roots.

What Is Crepe Myrtle – Things You Should Know

Crepe myrtle (or crape myrtle) is one of the most popular plants in the world, particularly in warmer climates.

There are many varieties and sizes of this plant available in the world. Generally, their size varies from 2 to 30 feet. When it comes to variations, it’s difficult for anyone to find a complete list of all varieties.

You can divide their sizes into three categories –

  1. Dwarf or miniature size – Grows up between 2 to 5 feet tall and wide.
  2. Semi-dwarf or medium size – The height is up to 15 feet tall and 10 feet wide.
  3. Large size – More than 20-30 feet tall and 15 feet wide.

When choosing a crepe myrtle, consider the area where you want to plant it, and then decide which height is perfect for the selected spot. If you want to plant indoors in a pot or container, try the dwarf variety.

The crape myrtles can flower in a wide range of colors such as purple, red, yellow, white, light to dark pink, lavender, magenta, and many other different shades.

The ideal time to plant these plants is early to late spring. Plant it in a sunny place where they can get enough sunlight. Suitable soil and a good drainage system are a must.

If you are planting them in the summer, make sure to supply adequate water. Take the best care of crepe myrtles. Fertilize them properly during the growing season. Prune in winter or early spring to promote more bloom.

Also Read: How to Keep Your Crepe Myrtles Free from Aphids

How to Fertilize Crepe Myrtle Trees

Crepe myrtles are heavy feeders, which means that they require more fertilizer than other plants. It is important to choose a fertilizer that has a perfect balance of nitrogen and phosphorus content.

As we said before, early spring is the best time to feed them with slow-release plant food, especially one containing iron or sulfur. You can also apply organic fertilizer.

Well-balanced fertilizer: Firstly, you need to choose a well-balanced fertilizer. The NPK ratio of a well-balanced fertilizer for crepe myrtles should be 8-8-8, 10-10-10, 12-4-8, and 16-4-8 (in different cases).

  • If you want to apply 8-8-8 or 10-10-10, for every 100 square feet of the planting areas, take one pound of fertilizer for dwarf varieties and small shrubs. The amount can increase for the large myrtles trees and shrubs.
  • If you are applying 12-4-8 or 16-4-8, follow the same instructions. Just use half a pound of fertilizer instead of one pound.

For newly planted crepe myrtle: Newly planted crepe myrtles should be fertilized in the first growing season. The University of Georgia suggests each of them needs one teaspoon of fertilizer per month for this season.

Before covering the plant root ball with soil, apply fertilizer around it. Then supply adequate water. Newly growing plants can be damaged by an early frost. Avoid fertilizing before the first frost date if you live in an area with a heavy frost. 

For mature crepe myrtle: Consider applying well-balanced granular fertilizer for mature crepe myrtle. The nitrogen ratio should be 10. When fertilizing, be aware that direct contact with the tree’s trunk is harmful. Just fertilize over the drip line area.

In containers and pots: If you grow crape myrtles in a pot or containers, apply a water-soluble or slow-release fertilizer. Before purchasing, check if the fertilizer is water-soluble or not. In spring, when you notice new growth, start fertilizing. Follow the product label for clear instructions.

Soil pH range: Before applying any fertilizer, testing the pH level of the soil is a must. If you don’t know the pH of your soil, test it. Crepe myrtles grow best in soil with a pH of 5.5 to 6.5.

Follow the manufacturer’s instructions: Remember to follow the manufacturer’s instructions to know the amount of fertilizer you need.

When Should You Fertilize Crepe Myrtles?

Fertilizing the crepe myrtle at the right time is necessary to achieve good growth, promote colorful blossoms, and have long-lasting health.

Though crape myrtles can benefit from fertilization anytime, the most vital time to fertilize is during the initial growing stage. When the plant is new and young, it requires more nutrition to establish strong, healthy roots.

Fertilize them throughout the first year of growth. Try to apply fertilizer once a month. The ideal time to fertilize is in early spring when they benefit most from feeding. After applying fertilizer, be sure to water the plant. Crepe myrtles need at least 1 inch of water per week.

Caution: Avoid over-fertilizing because it can negatively affect your plants. You may notice overgrowth by applying too much fertilizer, but fewer flowers will form.

Frequently Asked Questions (FAQs) on Fertilizing Crepe Myrtles

Why Is My Crepe Myrtle Tree Not Blooming?

There are many reasons behind the crepe myrtles tree not blooming, such as the lack of enough sunlight, water, and fertilizer. Lack of new stem growth and late or improper pruning method are other significant reasons for less blooming. Remember, you should not prune crepe myrtles before they bloom.

Over-fertilizing can also affect blooming. It can cause your crepe myrtle to grow quickly but at the cost of producing fewer flowers. Your trees will expend all their energy into growing.

Be patient. Wait until the second season comes for crepe myrtles’ to bloom. Some varieties of these newly planted crepe myrtles may not bloom until the second year.

How Can I Make My Crepe Myrtle Bloom More?

If you want to encourage more flowers during the blooming season, you should address any issues hindering your crepe myrtle. First, test the pH levels in your soil to ensure that you use the proper ratio of nutrients in your fertilizer.

For more blossoms, consider applying fertilizer containing low nitrogen and phosphorus. This is because higher nitrogen promotes plant growth instead of blooming. Additionally, you can add a little amount of bone meal around the tree. Fertilize in the spring and ensure that the soil is watered regularly.

Are Coffee Grounds Good for Crepe Myrtles?

Crepe Myrtles like coffee grounds because they contain the proper balance of nitrogen, potassium, phosphorus, copper, and magnesium. It is an effective natural solution to improving your soil structure and promoting the healthy growth of your crepe myrtles.

You can also protect your plants from insects and other diseases by applying coffee grounds. Aphids, sooty mold, and other common insects strongly hate the smell, texture, or acidity of it. You can use it in place of any other toxic pesticide that is harmful to the environment.

If the soil pH range is 6.0-6.5, there’s no need to apply coffee grounds. Coffee grounds can be beneficial for soil with a pH over 7.0.

Are Crepe Myrtle Trees Acid Loving?

Crepe myrtles grow well in acidic soil. Acid also helps to achieve more flowers that are larger and more vibrant. Crape myrtles prefer a variety of soils, from acidic to mildly acidic. Though the pH range of maximum garden soils is 6.0 to 7.0, the range of 5.5 to 6.5 is perfect for crepe myrtles.

If necessary, you can raise or lower the pH of your garden soil. Apply more sulfur to lower the pH and increase acidity. Apply agricultural limestone to raise the soil pH levels and decrease acidity.

Is Epsom Salt Good for Crape Myrtles?

Epsom salt helps to promote more green leaves, and flowers blooming. Epsom salt has micronutrients with sulfur, oxygen, and magnesium that help to attain healthier and faster growth for your plants.

To get rid of insects and some diseases, Epsom salt also works well. If you consider spraying leaves with Epsom salt, avoid doing so on hot sunny days.

Before applying, a soil test is necessary to know the pH level. If the pH is more than 6.5 and it has less acidity, a small amount of Epsom salt will work better.

How to Grow Crape Myrtle in Cold Climates?

Crepe myrtles do best in warmer climates, but growing them in a cooler climate is still possible. Though they will require extra care.

When planting them outdoors in cold climates, choose the warmest spot in your yard with the best access to sunlight.

If you want to grow them indoors, you plant dwarf varieties in containers. Select a big enough container so that they have space to grow.

Though the tree may look dead in the winter, the roots are still alive. In spring, they start to wake up gradually and get new green leaves and new growth. When you notice new growth, provide them with enough water and fertilizer.

Final Thoughts

Crepe myrtles are relatively easy to grow and maintain. The best quality fertilizer is important in maintaining your plant’s health and encouraging the growth of flowers.

We highly recommend you choose the best fertilizer depending on your needs by doing a soil test before purchasing any fertilizer.

Written by Sean Stratton

Sean Stratton

Hi, I'm Sean, the senior editor here at Fertilizer Pick. I grew up on a farm in North Carolina and have grown fruits, vegetables, and trees since childhood. While I no longer live on a farm today, I still enjoy spending time on my garden and sharing my knowledge with friends and fellow garden enthusiasts.