Crape Myrtle, also spelled as Crepe Myrtle, is the common name for Lagerstroemia, which is a genus of about 50 evergreen and deciduous shrubs and trees, from the Lythraceae or loosestrife family.
The plants are native to Southeast Asia, the Indian subcontinent, parts of Oceania, and northern Australia, but are widely cultivated in warmer regions, all around the world, including the United States.
Crepe myrtle plants yield colorful flowers in a variety of colors, from white to multiple shades of purple, pink, and red.
They also have a relatively long blooming period, which can go up to four months.
The flowers of these plants resemble the delicate and crinkled crape paper, hence, the common name.
Crape myrtles are widely cultivated, both commercially and as house plants, for ornamental purposes.
However, these plants require proper care and maintenance to stay healthy and continue to bloom.
Maintaining the right soil pH, proper drainage, adequate fertilization, and ensuring the plants are in full sun, have the right amount of mulching, and are not being pruned too aggressively – this is what you need to successfully grow Lagerstroemia.
Fertilizing, in particular, helps to maximize growth and blooming.
When crepe myrtle plants do not yield flowers or produce fewer or poor quality blooms, many a time, all they need is plant food and just fertilizing them is the solution to all these flowering issues.
However, you need to make sure to use the right amount of fertilizer at the right time to get the results.
Best Fertilizer for Crepe Myrtle
8-8-8, 10-10-10, 12-4-8, and 16-4-8 – all these different types of fertilizers can work well for crape myrtle plants as long as they are used in the right quantity.
If using an 8-8-8- or 10-10-10 fertilizer, use one pound of fertilizer for every 100 square feet of the planting bed for small shrubs and dwarf varieties.
For large crape myrtle trees and shrubs, increase the amount of fertilizer and use a pound of fertilizer per inch of the tree’s diameter.
However, if you are using a 12-4-8 or 16-4-8 solution, follow the same rate, but reduce the amount of fertilizer to half a pound.
Opt for a slow-release fertilizer, such as Osmocote, or any 10-10-10 all-purpose fertilizer containing trace minerals.
When and How to Fertilize Crepe Myrtle
Young and new plants have the highest need for fertilization.
Therefore, fertilize them three times during the first year of growth – in March, May, and then in late summer.
This helps to promote blooming in new plants later in the year i.e. fall.
Reduce fertilization once your crepe myrtle becomes established as they do not need much fertilizer.
Fertilize the mature flowering trees just once a year, before the new growth and flower buds emerge i.e. in early spring, to promote and maximize spring growth and blooming, later in the summer season.
Apply the fertilizer around the base of the plant, without removing the mulch, if it is present and water thoroughly after it as it helps the fertilizer to penetrate deep into the soil and reach the roots.
Make sure to not over-fertilize as it will cause excessive growth at the expense of blooms.
Stick to the fertilization schedule discussed above unless your crape myrtle plants lack essential nutrients, required for flowering, due to poor soil conditions.
For a crepe myrtle plants to properly use and benefit from fertilizer, make sure the pH of the soil is slightly acidic i.e. within the range of 5 to 6.5.
Your trees will not thrive and remain substandard due to lack of nutrients, if the soil’s pH is not right.