The most common reason for the rose of Sharon Leaves turning yellow is poor drainage, though there can be other causes. If you are sure the plant has proper drainage, other possible causes include a lack of iron, pests, or poor fertilization.
These plants are relatively easy to care for, and I have never found them troublesome once they have had the correct drainage and nutrients in the soil.
If you see yellow leaves on Rose of Sharon though, it is best to address the problem straight away. Use this guide to find out what is happening to your plant and get it on the road to recovery.
Rose of Sharon
The rose of Sharon isn’t technically a rose, despite the name. It's actually a member of the hibiscus family and traditionally represents ‘delicate beauty.’ This flowering bush is known for its large blooms of pink, white, and blue.
This beautiful plant is a great addition to any garden and is hardy and generally easy to care for. However, care must be taken to not let it take over your yard. Pull up the suckers that the plant sends out, and it will eventually stop producing them.
If your plant is turning yellow, there are a few common reasons, all of them fixable. Here’s a more detailed look at the reasons your rose of Sharon leaves may be turning yellow.
Poor Drainage
Even if you are watering your rose of Sharon appropriately, the roots can become waterlogged if the soil isn’t draining properly. Even if the topsoil appears dry, the water can get trapped. This will ‘suffocate’ the roots and cause their leaves to become yellow.
If you can, dig around the shrub and add a generous amount of compost or bark mulch into the soil. Make sure to dig deep enough to reach the bottom of the roots.
You may need to move the shrub if you cannot provide proper drainage where it is. Replanting the shrub in well-draining soil should correct the problem, and your leaves will turn back to green over time.
Chlorosis
Chlorosis is caused by insufficient iron in the soil. The condition will turn the plant yellow and eventually kill it, so it is important to treat the disease quickly.
If you see that the leaves are yellow, but the veins remain green, then it is likely that this is what is affecting the plant. It also typically affects new growth leaves before the older ones.
The condition is caused by one of four different factors:
The Soil pH Is Too High
You can test the soil’s pH with a soil test kit. If the pH is over 7, it restricts the rose of Sharon from pulling iron from the soil.
The Soil Has Too Much Clay
Clay soil lacks organic material and this lack of trace nutrients stops the rose of Sharon from getting enough iron from the soil. Work organic material, such as peat moss, into the soil to correct the problem.
The Soil Is Compacted
If the soil is too compacted or wet, it blocks airflow and will hinder the plant’s ability to take up iron as. You may need to move the plant to correct for these qualities in the soil.
If you cannot, there are other ways to get iron to the plant. Use chelated iron as a foliar spray or soil supplement to make more iron available to the plant and counterbalance the soil, allowing the plant to get enough iron.
The Soil Has Too Much Phosphorus
An overabundance of phosphorus can block the plant from getting enough iron. If a soil test kit shows a high reading of phosphorus, use a fertilizer that is lower in phosphorus to rebalance the soil.
Pests
Overall, I have found that these shrubs are quite resistant to pests, but you may find that aphids or whiteflies are causing the yellow leaves of your plant. They sap the nutrients from the plant and cause yellow leaves.
The most common pests to cause problems for the rose of Sharon are aphids and whiteflies. If you see these small insects on your plant, don’t panic.
They are fairly easy to manage with a regular application of insecticidal soap or horticultural oil. Even a strong spray of water should rid most of the insects from the leaves. With these pests gone, the plant will return to normal coloring before long.
Inadequate Fertilization
A lack of nitrogen can be another reason that your Rose of Sharon leaves is turning yellow. If you have ruled out all of the other causes above, use a soil test kit to see if there is a lack of nitrogen in the soil.
Mixing in a balanced fertilizer with nitrogen will fix the problem. However, do take care not to over-fertilize the soil as this can ‘burn’ the shrub and also leave you with an unhealthy plant.
Frequently Asked Questions
Have more questions about your rose of Sharon? Here are some answers to other common questions.
Q: What is the lifespan of a rose of Sharon?
A: These shrubs, well cared for, have a long lifespan of about 30 years.
Q: Are rose of Sharon's invasive?
A: As they spread easily, the rose of Sharon can be considered invasive. However, dead-heading spent blooms can easily stop their spread. You can also find varieties that do not spread.
Q: When do rose of Sharon bloom?
A: These shrubs bloom from mid-summer through to fall.
Q: Do rose of Sharon come back each year?
A: Yes, the rose of Sharon is a deciduous bush, meaning it will lose its leaves each winter, but it will return in the spring.
Q: How fast do rose of Sharon's grow?
A: These plants are relatively fast-growing, with a growth rate of between 13 and 24 inches per year.
Rose of Sharon Leaves Turning Yellow – Conclusion
By far, the most common reason for these shrubs to turn yellow is improper drainage and this is the most important thing to ensure the health of your rose of Sharon.
If this isn’t the issue, go through this list to diagnose your plant. Once you find out what's wrong, it should be easy to return these beautiful shrubs to health and have them brighten your garden again.
Check out our other plant health guides for Sago Palm and Sunflower.