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8 Reasons Why Your Crape Myrtle Might not Bloom as Expected

8 Reasons Why Your Crape Myrtle Might not Bloom as Expected

This stunning evergreen tree is best known for the beautiful blossoms it produces in the summer months.

Native to south east Asia and Oceania, the crape myrtle is officially known as the Lagerstroemia. 

They can be grown as large trees or kept maintained as smaller ornamental shrubs.

Their stunning flowers – usually visible from early summer right through to the fall – are the key feature. 

Colors of the blossoms range from white, pink and red through to dark purple.

But what if you are struggling to get your crape myrtle to bloom?

Let’s troubleshoot together. 

 

Why is my Crape Myrtle not blooming?

Crape Myrtles need over 6 hours of full sunlight in order to bloom properly. If you are keeping it as a shrub in particular, make sure it is not overcrowded by other plants or shaded by garden sheds or other structures. Fertilize with a low nitrogen content fertilizer in the late winter or early spring, and never prune the tree before the blooming season. 

 

1. Lack of sunlight

The crape myrtle is native to southeast Asia and is found growing naturally also in Australia. As a result, it is no surprise that the tree requires a lot of sun.

Certainly, anything less than 6 hours a day will be detrimental to any blooms. 

If possible, try to plant in an area that will receive more than 8 hours of sun in the high season. Be aware too of any shade that will be projected onto the shrub by larger trees or even houses in the vicinity. 

 

2. Lack of new growth during the spring

One of the key reasons you may not get summer blooms on your crape myrtle can actually hark back to the spring season. The tree produces summer flowers on new growth.

So if you did not experience rapid spring growth to the stems, this can be one reason why you are not getting any flowers. 

Make sure you apply some fertilizer to the area in the later winter or early spring to promote new stem growth – and therefore more coverage for potential flowers!

Ensure however that your fertilizer is not dominated by nitrogen – this will promote nice foliage but few flowers. Look for a treatment that has more phosphorus content. 

 

3. Fertilizing other plants or lawns near your crape myrtle

If you have placed fertilizer near the shrub on other plants or lawns, then this can also be an issue. This is a common problem especially if you have used a high nitrogen content fertilizer to promote growth of a lush green lawn. 

Try to separate the area and keep plants with different fertilizer needs away from your crape myrtle. 

 

4. Incorrect pruning – especially on new growth

Since we know that the crape myrtle flowers on the newest spring growth, make sure you are careful when pruning.

Only prune old growth back if possible, and let the new stems grow in order to give you the best flower coverage.

Often you may receive the recommendation to prune on new growth in order to get the tree to grow faster, but this will be at the expense of the blooms, so tread carefully.

The easiest way to manage this is not to prune the tree before it blooms. 

 

Pruning for optimal growth

When you do prune, prune away at old deadwood. This will bring more light to the rest of the tree and will also circulate the air around the stems better. 

 

5. Infections or infestations

Some infections or unwanted visitors can also stop the tree from flowering. Watch out for fungal infections such as leaf spot. 

Whilst this is unlikely to kill the tree itself, it will reduce the blooms as the infection takes hold. Using a fungicide may help, but this is hard to manage on larger trees. You might just have to wait it out. 

Keep an eye out too for infestations of insects. Aphids or whiteflies are the most common unwanted pest that can cause your crape myrtle to not flower. 

 

6. Expecting blooms too soon

Different varieties of crape myrtle bloom at different times.

And generally, they won’t bloom in line with other trees such as cherry trees. If it is your first season, they may just be getting established. You may just require some patience in this matter!

 

7. Incorrect soil type

The crape myrtle prefers soil that will be well-draining with a pH of around 6. A clay-based or loamy soil will be the best option. You can try to mix soil that is poorly draining with sand to improve its content and promote growth. 

 

8. Inadequate amount of water

Make sure your crape myrtle is getting around one inch of water a week in the growing season when it is young, otherwise it will refuse to bloom entirely!

Note however that a mature crape myrtle is actually drought-resistant. 

 

Frequently asked questions about crape myrtles that do not bloom

 

What fertilizer is best for a crape myrtle to encourage flowering?

Apply a phosphorous-based fertilizer to the tree in the late winter or early spring to encourage optimal flowering. Make sure that the content does not contain more nitrogen than phosphorous. 

 

How much sun does a crape myrtle need?

A crape myrtle needs at least 6 hours of sun per day during the high season – preferably 8. If you are planting this shrub outdoors, consider current shade patterns and bear in mind that other plants or trees may grow and overshadow your crape myrtle in future years. 

 

Conclusion 

Ensure you follow these basic principles for pruning, fertilizing and caring for your crape myrtle and you should have fabulous blooms for up to three months in the summer!