3 Reasons for White Spots on Rosemary [Actionable Solutions]

Rosemary, the fragrant and evergreen beauty of most of the home gardens is a shrub of the Mediterranean region. It’s quite resistant to several injuries due to adaptation in such an extreme climate. But that doesn’t mean it can withstand different adverse conditions.

Most of the time gardeners face troubles while growing rosemary. We know that you are not indifferent to them. If you are wondering what causes white spots on your rosemary and how to get rid of them, you are in the right place.

We are going to discuss some major reasons related to this which include fungal attack, pest infestation, and white spots due to cold water.

So, let’s get down to the business-

Why are The White Spots on My Rosemary?

1. Fungal Attack

Rosemary is highly prone to fungal attacks. This may occur in various forms in plants and is the main culprit of white spots and fuzzy outgrowths.

You may have noticed some white powdery flakes on your rosemary. These occur due to powdery mildew. This disease may not kill your plant, but will definitely make them weak.

It’s quite easy to diagnose powdery mildew. A white powdery coating on leaves is visible in this case. This powder is the little spores of fungi, which transmits rapidly to other plant parts. So, it’s necessary to control this disease as soon as possible.

Downey mildew is another form of attack where white spots are visible to the lower surface of plant leaves.

Whitish-grey mold on dried rosemary develops in wet and humid conditions. These may also infect fresh rosemary leaves and woody stems.

Grey or white fluffy spots are indications of mold development.

Fungal growth eventually destroys all your spiny beauties. So, it’s very much important to control these as soon as possible.

Control Measures

Controlling fungal disease in different plants is almost the same. But you have to keep in mind that rosemary is an edible herb. So, how do you treat rosemary fungus? Not that tricky actually. Let me show you how.

Let’s start with an easy one. First of all, start by giving your plant a good water splash. This will remove sticky saps and cottony residue of fungus.

Next, all you have to do is rubbing the affected leaves carefully to get rid of the remaining ones.

You can shift your rosemary from a high humidity area to an open place. This will reduce the infection severity.

Immediately remove any shed leaf affected by the fungus to avoid soil transmission.

If you are still not being able to control, it’s better to switch to a fungicide formulated for edible herbs like rosemary. Copper sulfate-containing ones are a good option. (Our Pick: Bonide Copper Fungicide)

We can also suggest you an organic formulation. Commercially concentrated neem oil-based fungicide can help you. (Our Pick: Garden Neem Oil Extract Concentrate) Some repeated uses may be needed depending on infection severity.

Home Remedies

#Recipe 1: Baking Soda Spray

Ingredients:

  • 1 tablespoon of baking soda
  • 1 liter of water
  • Some drops of liquid soap

Steps:

  • Add baking soda to water as a mentioned ratio.
  • Then put some liquid soap to it
  • Prepare a spray out of this mixture and apply it to your plant.

#Recipe 2: Chamomile Tea

Ingredients:

  • 1 tablespoon of chamomile tea.
  • 500 milliliters of water.

Steps:

  • Soak chamomile tea in warm water for 5-10 minutes.
  • Let the mixture cool down.
  • Pour it in a spray bottle and apply to the targeted area

Preventive Measures

It’s always better to prevent some conditions before these become fatal for your plants. Here are some of our suggestions to avoid any kind of fungal infestation. So, let’s get to it.

Before planting make sure that you are maintaining proper spacing in between your plants. This will allow proper air circulation to avoid wet conditions.

Practice proper watering. Don’t go for overhead watering so much.

While harvesting or pruning, be careful that all the morning dews have dried up. Or you can simply do these kinds of stuff in sunny weather.

Don’t forget to disinfect your garden pruners.  Rubbing alcohol and phenol-based cleaners can effectively remove any residue.

2. Pest Infestation

Pests are the frequent enemies in shrubs. Rosemary is not different from these. Due to pest infestation, plant leaves can develop white spots.

Yellowish-white spots are a result of this. Mainly sucking insects do this sort of injury.

Namely leafhopper, spider mites are the little evils in this case. They suck the sap from the bottom of the leaves and thus cause tiny white spots on rosemary. Sometimes striplings are also visible on leaves.

Other insects like aphids, scale insects, and mealybugs leave some sticky white substances on rosemary after feeding. These substances highly encourage fungal growth in the plant.

Control Measures

First of all, start by giving your plant a good water splash. This will remove sticky saps and cottony residue

Commercially concentrated neem oil spray is a good pick for these insects. Normally 2% concentration is safe for edible plants. Just follow the instructions provided.

Another inexpensive option can be an insecticidal soap (our pick: Natria Insecticidal Soap).

You can use any of them or can alternate the sprays. First apply neem spray, next follow with the insecticidal soap spray after 2-3 days.

A little amount of rubbing alcohol can remove any insect residue reducing the risk of further pathogen attack.

If all these fail, you can simply rely on a pesticide formulated for houseplants(our pick: Monterey organic Garden Insect Spray)

Home Remedies

#Recipe 1: Homemade Insecticidal Soap

Ingredients:

  • 1 tablespoon of vegetable oil.
  • 1 tablespoon of castile soap.
  • 3.5 liters of water.

Steps:

  • Mix vegetable oil and liquid soap together.
  • Add this mixture to the water.
  • Pour the solution into a spray bottle and apply to the upper and lower leaf surface.

Caution – Don’t use any other soap except castile soap as degreasers in those can damage your plant. If you can’t find this soap it’s better to use a commercial insecticidal soap instead.

#Recipe 2: Chili Spray

Ingredients:

  • 4 tablespoons of fresh or powdered chili.
  • 2 liters of water.

Steps:

  • Carefully crush chilies or add powdered chilies to water.
  • Let it rest for some time.
  • Sieve the mixture
  • Shift the liquid into a spray bottle and use.

Caution –Be careful while mixing as chilies can cause severe eye and nasal irritation. Use gloves while making this spray.

3. Cold-Water Spots

Coldwater spot often occurs in indoor conditions. If you are using water directly from the tap, the thermal shock can tear down the palisade leaf cells leaving a white callous behind.

Sometimes minerals from the tap water can pile up and appear as white spots on leaves.

Normally these white spots do not do any harm to your plant. But you can’t get rid of them without cutting the affected leaf. So, you might be thinking about how to treat this type of white spot on rosemary. Here are some tricks and tips for you. Keep reading.

Control Measures

Don’t use cold water straight from the tap. This can help to reduce these white spots.

You can also follow the bottom water technique. All you have to do is put your potted rosemary in a tub with a few inches of water in it. The drainage hole will allow soak up the water without any direct shock to the plant.

In case of mineral accumulation, you can use a water filter or simply put purified water on your plants.

Home Remedy

A diluted vinegar solution can minimize the visibility of those mineral build-ups. Here is a recipe for you.

Ingredients:

  • White vinegar.
  • Distilled water.

Steps:

  • Mix vinegar and distill water in a 1:1 ratio.
  • Spray this solution to your plant.

FAQs

Is it safe to eat rosemary with white spots?

Well, it depends on how you treat them before using them. Mainly most of the white spots are some sort of external growth. So, proper washing before consumption can easily remove all these.

Clean your herbs by rubbing them thoroughly. Then these are safe for further use.

In case of dried rosemary, you can remove it only by rubbing them. After that put them in direct sunlight for some time. You can also oven dry a bit.

If there is any internal injury, just cut that portion and use the rest. However, it’s better to avoid affected rosemary for the person suffering from any sort of allergy to fungus.

Is powdery mildew harmful to humans?

Powdery mildew is a plant fungus that generally doesn’t do any harm to humans. So, you are not getting infected by just touching them.

But this fungus can indirectly cause harm if swallowed with food. So it’s advised to remove all the fungal residue before usage.

Conclusion

In this article, we have tried to provide a guideline on how to get rid of white spots on your rosemary leaves. It doesn’t seem to be that hard, right? Exactly!

All you have to do is try to avoid humid conditions as much as possible, treat the infected plants as we have mentioned, and just keep an eye on further attacks.

So what are you waiting for? Start pampering your rosemary and enjoy the fresh aroma with some lovely blooms. Don’t forget to inform us about how these worked.

Leave a Comment