5 Reasons For Rhubarb Leaves Turning Yellow [How To Fix]

Rhubarbs are mainly grown for their fleshy edible stalks. But when the leaves are turning yellow it can affect the taste of the stalks too. So, when you see the leaves are yellowing it’s time to go to action. If you take the right measures you can keep having the juicy stalks year after year.

Let’s begin with the reasons so you can decide how to fix the problem.

The 5 reasons for Rhubarb leaves turning yellow are Watering, Soil and Temperature, Nutrient Deficiencies, Fungal Attacks, and Pest Problems.

This article will walk you through the problems and help you find out the solutions. 

So let’s get started-

Why are My Rhubarb Leaves Turning Yellow?

1.Imbalanced Watering

Improper watering is one of the main reasons why your rhubarb leaves are turning yellow. Rhubarb plants have broad leaves. So, they need a lot of water to grow. Especially if you are growing in warmer zones. 

But if you overwater them the bottom leaves of your rhubarbs will wilt and start turning yellow. Correct watering is very crucial. Because when they are watered properly they store large amounts of food in their roots. And produces a good harvest.

Control Measure

If you are watering your Rhubarbs every day it’s getting too much.

Getting a moisture meter will help you determine what amount of water to apply. We recommend Atree Soil Soil Tester Kits with Moisture, Light, and PH Test for Garden

Water every other day during summer if there’s no rain. Remember overwatering will encourage fungal growth and slugs. You can cut those yellow leaves off with a sharp pruning shear to help new leaf growth.

2.Soil & Temperature Problem of Rhubarb

Rhubarb likes well-drained soil. It should be moist but not waterlogged. If the soil is sandy, rhubarbs will lack nutrients. And this will result in yellow leaves. 

Rhubarbs grow in acidic soil conditions. The pH requirement is 6-6.5. So, even if your soil is well-drained, alkaline soil can turn the rhubarb leaves yellow. Check the soil pH with a pH meter to check the soil acidity level.

Rhubarb grows best in cold temperatures. It’s even better for them if the weather is occasionally below 40 F. If you are wondering why your rhubarb leaves are turning yellow, they might be getting too much heat.  

Control Measure

Now the question is how to revive the rhubarb plants?

Improve the soil quality by adding some well-dried cow dung and manure around the plant. Make sure the soil has good drainage. Poor drainage brings lots of other fungal diseases to Rhubarb.

When the soil is alkaline, add acidic materials to restore the balance. Once they start getting enough nutrients the rhubarb plants will revive themselves automatically.

Rhubarbs need partial sun. So, give them some afternoon shade with a screen. But make sure they get the filtered sunlight. They don’t do much well in humid conditions also. So, make sure the airflow is good around them. Good airflow will help to prevent fungal growth.

3.Rhubarb’s Nutrient Deficiency

Nutrient deficient Rhubarb leaves will turn yellow and wilt. Iron and Nitrogen are very vital for Rhubarbs. Without enough nitrogen, they cannot make enough food so they get rid of the leaves. This is when the yellow leaves start falling off.

Control Measure

Fertilize your Rhubarbs in the early spring. Pick a fertilizer for your Rhubarbs that will balance their Nitrogen and iron requirement (our pick: Miracle-Gro Water Soluble All Purpose Plant Food)

You can also apply blood meal, bone meal twice a year to provide more nutrients.

4.Crown Rot & Leaf Spot Of Rhubarb

Leaf spots are common in Rhubarbs. Big yellow patches form on the leaves and it looks like the leaves are turning yellow. Eventually, the leaves start falling off.

Crown rot is a deadly disease of Rhubarbs. The roots get black lesions and the leaves start turning yellow and fall off. 

Control Measure

The best way to start treatment is by removing all the infected yellow Rhubarb leaves.

Then you need to be careful when picking a fungicide. Apply a mild fungicide that’s not harmful to the edible stalks.  (our pick: Bonide Copper Fungicide)

Here are 2 amazing DIY natural home remedies you can try for leaf spots and crown rot:

Recipe 1:- Baking Soda Recipe

Ingredients:

  • 1 tablespoon of baking soda
  • 1 teaspoon of liquid dishwashing soap
  • 1 gallon of water

Steps:

  • Mix these ingredients and put them into the sprayer
  • Spray on both sides of the rhubarb leaves and stalks
  • Do not store the leftover mixture. 

#Recipe 2:- Cinnamon Spray Recipe

Ingredients:

  • 2 tablespoons of cinnamon powder 
  •  1 liter of water 

Steps:

  • Mix them together
  • Let this solution rest overnight 
  • Then strain with a fine cloth and pour it into the sprayer.
  • Spray on both sides of the rhubarb leaves. 

Preventive Measure

Don’t grow rhubarbs in the same place for more than 2 years. While throwing away the infected leaves make sure they don’t come in contact with other plants or garden tools. Do not let the Rhubarbs stay in waterlogged conditions. 

5.Pest Attack on Rhubarb

It’s very common for rhubarb leaves to get attacked by slugs and aphids. They suck the leaf sap and turn the leaves yellow. These bugs should be killed right away. Because aphids transmit black mold and slugs create holes on stalks and the bottom leaves near the ground.

Control Measure

Aphids are very small and hard to notice. But they secrete a sticky substance. So, by seeing this on your leaves you can be sure it’s aphids. Get the best and safest insecticide for your edible rhubarbs (our pick: Monterey Garden Insect Spray)

Insecticides are not effective against slugs. For them try Snail and slug Killer (our pick: Monterey Sluggo Wildlife and Pet Safe Slug Killer)

Try these homemade insecticide recipes for your rhubarbs:

#Recipe 1:- Horticultural Oil Recipe

Ingredients:

  • 2 teaspoons of liquid soap 
  • 1 cup of any oil like soybean oil or olive oil or vegetable oil. 

Steps:

  • Mix these ingredients very well and store the mixture in a bottle.
  • Add a tablespoon of this mixture with every 500 ml of water and pour it into the sprayer.

#Recipe 2:- Three-In-One Insect Spray Recipe

Ingredients:

  • One small bulb of garlic
  • one small onion
  • 1 tablespoon of liquid dish soap

Steps:

  • Make a paste of garlic and onion
  • Strain the mixture with a fine cheesecloth
  • Now add the liquid soap and mix very well
  • Now make it a 2-liter solution by adding water.
  • Spray it on both sides of the rhubarb leaves

Frequently Asked Questions (FAQs)

Should I Remove Yellow Leaves From The Rhubarb?

Removing the yellow leaves is a good idea. This way the injured leaves are gone and new leaves can grow in their place.

Should I Remove Dead Rhubarb Leaves?

Any dead leaves should definitely be removed. Especially if they are fungal affected. Because these dead leaves can infect fresh leaves. Remove them carefully and put them in the garbage.

Conclusion

I have tried to include every possible information about the rhubarb leaves turning yellow. I hope you found this article resourceful. 

Rhubarbs are pretty hardy plants. Just water them the right amount and prevent fungal and pest attacks. The yellow leaves will be turning green again in the spring. 

Let us know if you have any further questions about Rhubarb care and we will get back to you with the answers. 

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