5 Reasons Why Rosemary Leaves Turning Yellow [Solutions]

Rosemary plants are very hardy and they don’t require much maintenance. However, sometimes they fall victim to some environmental stress and the leaves start turning yellow.

Rosemary is used in culinary items. So, yellow leaves are a big concern for any grower. Because nobody wants to serve yellow rosemary leaves in their dishes.

Don’t worry! you can treat these yellow leaves if you take the right approach. The main question; why are the rosemary leaves yellowing?

There are 5 Problems that cause yellow leaves in rosemary including Imperfect Watering, Nutrient Imbalance, Extreme Heat, Insect Attacks, and Diseases.

In this article, I’m going to discuss all these problems and tell you how to solve them.

So, without making any delay let’s get started-

How to Get Rid Of Yellow Rosemary Leaves

1. Imperfect Watering on Rosemary

The rosemary leaves turn yellow if they are either underwatered or overwatered. When they are overwatered the leaves will turn yellow and wilt. But if they are underwatered they will be turning yellow and fall off.

Overwatering also encourages fungal diseases so it’s really important to water them correctly. Too much water stress for a long period can even kill your rosemary plant.

Control Measure

Rosemary does not like much moisture. It’s best to check the soil with a moisture meter so that watering is no longer a problem (Our pick: Atree Soil Soil Tester Kits with Moisture, Light, and PH Test for Garden)

The rosemary yellow leaves will revive naturally when it starts to get proper water. If the soil is too dry, water enough to make the soil wet but not soggy. Make sure the soil is not waterlogged.  

If you have potted rosemary make enough drainage holes for water movement.Place tray filled with water and pebble underneath the pot.

2. Extreme Heat

Another reason why your rosemary leaves are turning yellow is too much sun exposure and heat. The tissue of the leaves gets burned and they start getting yellow.

Again if they don’t get enough sunlight they cannot make enough food for themselves. The leaves can turn yellow. As a result, the leaves become yellow.

Control Measure

Make sure they get 7-8 hours of sunlight. But when the temperature is too high, provide some shade or bring them indoors. In the case of indoor potted rosemary, bring them outside for some sun exposure.

3. Nutrient Imbalance Of Rosemary

Rosemary is native to soil with low nutrient availability. Overfertilization of nitrogen is one of the reasons why leaves turn yellow.

Again some nutrient deficiency makes the lower leaves yellow and some other deficiency makes the upper leaves yellow.

Control Measure

Get the best herb fertilizer for your rosemary plant(our pick: Jobe’s Organics Herb Plant Food). And apply during spring and summer according to the label instructions. In the case of potted rosemary, put a small amount of fertilizer in the soil keeping it away from the roots.

4. Insect Attack On Rosemary

Insects like thrips, whiteflies, spider mites, and aphids suck saps from the leaves. Their feeding causes the leaves to turn yellow. The tiny insects are not easy to notice. They stay at the lower side of the leaves.

You should get rid of the insects as early as possible because these also bring many harmful viral diseases.

Control Measure

Rosemary is a cooking herb. So before choosing any chemical insecticides we have to make sure they are safe. Apply the best insecticide on your rosemary that is effective and chemically safe (our pick: Monterey organic Garden Insect Spray)

You can also spray neem oil and insecticidal soap. Or, you can also make insecticides at home. Here are some easy recipes for homemade insecticides:

#Recipe 1:- Neem Oil Recipe

Ingredients:

  • 1 tablespoon of neem oil 
  • 2 liters of water 

Steps:

  • Add these ingredients together and spray on the rosemary plants every week.

#Recipe 2:- Horticultural Oil Recipe

Ingredients:

  • 2 tablespoons of liquid dish soap 
  • 500 ml of any cooking oil like olive oil or vegetable oil. 

Steps:

  • Add these ingredients and mix very well
  • Store the mixture in a bottle.
  • Add a tablespoon of this mixture with every cup of water and pour it into the sprayer.
  • Spray on your rosemary plants twice a week until the pests go away.

#Recipe 3:- Basil Leaf Insecticide Recipe

Ingredients:

  • 2 Cup of fresh basil leaves
  • 1 tablespoon of liquid dish soap
  • 2 liters of water

Steps:

  • Bring the water to a boil 
  • Then remove it carefully from the heat
  • Now add the basil leaves and cover the pot with a lid
  • Let the water fully cool down 
  • Then strain the leaves from the water
  • Mix the liquid dish soap and 
  • Put the mixture into the sprayer
  • It’s very effective against aphids and whiteflies

Note: While applying any of these homemade recipes always use a small amount to test first in a small leaf. If the leaf seems okay then apply to the whole plant. If the leaf burns then dilute the recipe by adding water and try again on a small leaf.

5. Diseases of Rosemary

Root rot causes the leaves to turn yellow. The roots get affected by fungus. So, the water and nutrient uptake by roots is hampered. As a result, the leaves don’t get enough food and turn yellow and wilt.

Control Measure

Remove the infected yellow leaves and dispose of them carefully. Wrap them in a bag and throw them in the garbage. Then you need to apply a good fungicide to your Rosemary. There are so many fungicides available in the market. You need to pick one that is herb-safe (Our Pick: Bonide Copper Fungicide)

Make sure you always follow the directions carefully, Note when it’s safe to harvest your Rosemary leaves after the fungicide is applied.

Try these DIY homemade fungicide recipes and apply on your rosemaries:

#Recipe 1:-Cinnamon Spray Recipe

Ingredients:

  • 3 Tablespoons of Cinnamon
  • 2 Liters of water

Steps:

  • Mix water and cinnamon together and shake
  • Let it sit for overnight or 5/6 hours 
  • Strain the mixture with a fine cloth
  • Put the mixture into a spray bottle
  • Spray it on your infected rosemary leaves twice a week until the problem solves.

Recipe 2:-Baking Soda Spray Recipe

Ingredients:

  • 2 teaspoons of baking soda
  • 1 teaspoon of dishwashing liquid
  • 1 teaspoon of any cooking oil 
  • 2 liter of water

Steps:

  • Add baking soda and cooking oil to a mixing bowl and add the liquid soap
  • Then mix with water and stir slowly
  • Then pour it into the sprayer.
  • Spray on your rosemary plants up to twice a week.

Preventive Measure

Fungal problems occur in damp places where airflow is not good. So the best way to prevent root rot is by planting the rosemaries in well-drained soil with good air circulation. Prune off some leaves to provide good airflow. Water the rosemary in the base during the morning so the leaves don’t stay wet. 

In the case of potted rosemary If the soil is too soggy, dig up the plant. And replant it in a better potting soil mixture (our pick: Espoma Organic Potting Mix)

Frequently Asked Questions (FAQs)

Can I Eat Rosemary With Yellow Leaves?

If the yellow leaves are for water stress or heat stress then you can eat the yellow leaves after treating them. But if it’s due to fungal or insect attacks then you should not eat them.

Can I Use Moldy Rosemary?

Moldy Rosemary should not be used. Because the molds are not safe. They can create health hazards.

Conclusion

It’s very common for rosemary leaves to turn yellow. Especially when they are wrongly watered. Besides insect and fungal attack also causes yellow leaves. Keep an eye on your plant and find out what’s bothering it. 

I hope this article helped you find the problem along with its solution. When you see your rosemary leaves turning yellow or yellow spots, use the best quality fungicide and insecticide for them. Provide them with balanced nutrients. With your little help, your rosemary will produce plenty of green leaves.

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