Crown of Thorns Leaves Turning Yellow: Why?

Petals and Flower of Crown of Thorns
Crown of Thorns (Source: Pixabay)

Did you know? The Crown of Thorns got its name because it resembles the spiky Crown worn by Jesus during his crucifixion with the red flowers representing his blood.

Well, the backstory indeed is terrifying. But that is balanced by how regal this plant looks. You wouldn’t want to blemish its stunning look unless…

Crown of Thorns leaves turning yellow can be out of many reasons: improper watering, inadequate sunlight and temperature, and lack of nutrients.

Crown of thorns with beautiful red flowers and thorns
Crown of Thorns (Source: Pxhere)

Euphorbia milii, commonly known with names like Crown of Thorns, Christ Thorn, Christ Plant, etc., produces various colored flowers.

This article will talk about the yellowing of leaves, any precautions to adopt, treatment to revive, and some tips and tricks for our plant lovers out there.

Crown of Thorns Leaves Turning Yellow: Is it Normal?

In most cases, the yellowing of Crown of Thorns leaves is a normal phenomenon and nothing to worry about.

It’s the severity of the cause that you must be afraid of.

You can revive and nurse the plant back to total health if you diagnose the cause in its early stages. You can bid adieu to your plant if it’s too late.

Crown of Thorns
Crown of Thorns (Source: Wikimedia)

If you come across a yellow leaf, do not think that nursing it back to health is a lost cause. You can prevent it from dying.

When my Crown of Thorns turned up its first yellow leaf, I panicked to the core. And guess what? I overdid things.

I overwatered it, increased the humidity around the plant, and similar mistakes, and what did I get? A Crown of Thorns that succumbed to my denseness.

But don’t you worry, you can learn from my mistakes and avoid the same fate for your plant.

Why is my Crown of Thorns’ Leaves Turning Yellow?

There may be several reasons why your leaves of Crown of Thorns are turning yellowing.

It may be due to over/underwatering, lack of sunlight, or nutrition. Some of them are explained below.

1. Improper Watering

The Crown of Thorns does not require much water to thrive as a desert plant and a succulent.

But that doesn’t mean you torture your plant by providing it with little to no water it needs to function correctly.

If your plant is underwatered, it may showcase symptoms like yellowing leaves, droopy appearance, wilting of plant, etc.

Green sprout in a pot with water please sign
Green sprout in a pot with water, please sign (Source: Stocklib)

But wait, your plant is succulent. It has juicy leaves that store a lot of moisture. It has bigger enmity with overwatering rather than underwatering.

Overwatering the plant can inhibit proper growth, and the plant will show symptoms like dropping and yellowing leaves, rot in the stem, absence of new growths, etc.

Too much water can damage the Crown of thrones at the cellular level. If the case is too severe, the plant is at risk of getting root rot.

Proper Watering Tips

  • Ensure the pot you use for the Crown of Thorns has suitable holes and provision for drainage. Water accumulation can be dangerous.
  • Christ Plant is not a sucker for soggy soil. It can withstand drought more than it can withstand drenches.
  • Let the top 50% of the soil dry out between watering, but remember, the plant may incur damage if you do it for an extended period.
  • If your plant is settled in a brighter location, it may require more water comparatively.

For 5.5 inch pot, if your plant gets direct sunlight, water 1.1 cups of water every nine days. If not, water 1 cup of water every 12 days.

  • Water-less frequently in the winter season after the flowers fall off.
  • Make sure your potting mix has fine drainage. You can also add pumice, sand, or perlite to enhance drainage.
  • In winter, you can add water once the soil dries to a depth of 2 or 3 inches or 5-7.5 cm.

2. Inadequate Light

Another factor to consider with the Crown of Thorns is sunlight. They thrive in full light, similar to their natural environment.

Crown of Thorns despises locations where the light is not adequate. To show stress, their leaves may lose their color and turn yellow.

Importance of Sunlight for Plants
Importance of Sunlight for Plants (Source: Wikimedia Commons)

Take a book to your plant’s location, and try reading it. If you can’t read it without any artificial lights, your plant needs relocating.

Lack of light directly hampers the plant’s ability to produce chlorophyll, the green pigment on plants, and the plant appears yellow.

Place your plant at a place where it gets a few morning or evening hours. Succulents like Crown of Thorns need at least four hours of full bright sunlight per day.

Not only for survival, but if the plant gets enough light, it will produce beautiful and colorful blooms.

During winter, your plant prefers a spot near a west or south-facing window indoors and full sun for four hours outside.

800 Foot-candles of light is good for the plant’s optimum growth, whereas it needs at least 400 Foot-candles for survival.

When the light is scarce in overcast or winter conditions, you can use artificial grow lights as supplements.

3. Lack of Proper Nutrients

Tropical plants like Crown of Thorns do not usually need nutrients. But for optimal growth, the use of some fertilizer might help.

Not getting enough nutrients can cause the leaves to turn yellow, while high-phosphorus fertilizers can help mature plants bloom.

The University of Maryland Extension says, yellowing first appears at the veins of the older leaves.

Your plant needs nitrogen-rich fertilizer to ensure that it gets all the energy whenever required. Lack of it can affect the leaves by turning them pale to yellowish-green.

Water-soluble fertilizer diluted to half strength is perfect for the best growth of  Crown of Thorns.

Fertilize every two months during summer and every three months during winter.

Lack of nutrients shown in plant
The effect of lack of nutrients in plants. (Source: Wikimedia)

The temperature and water affect the nutrition uptake in the plants. So basically, you need to take care of the draining section. Use a pot that has proper draining holes.

Other signs of lack of nutrients include stunted growth and change of the leaf color to dark-bluish green.

Nourishing Tips

  • Treat your plant with a high-nitrogen nutrient formula to fulfill the lack of nitrogen.
  • Fertilize the plant with a diluted 10-10-10 ratio fertilizer.
  • You should feed your plant at least one time a month during spring and summertime.
  • Nitrogen availability is impacted by soil pH as well. Keep a pH of 5.5-6 for the Crown of Thorns.
  • Use any “cactus” labeled fertilizer as it fulfills all the required 13 macro and micronutrients.
  • If your plant cannot absorb nutrients from the soil, you can add slow-releasing liquid fertilizer.

4. Extreme Temperature Fluctuation

As you must know, the Crown of Thorns is a tropical plant, and tropical plants like warm to high temperature, so they prefer high temperature by associative law.

Although they are hardy plants to grow, they are pretty sensitive about their temperature.

Yes, they can withstand temperatures as low as 35°F and above 90°F, but they hate extreme fluctuations in temperature.

Temperature in relation to plant's growth
The temperature in relation to plant’s growth (Source: ResearchGate)

But if you ask me the optimum temperature for the plant, it’s between 60°F to 80°F.

Remember! When the temperature during day time is at peak, you should water the plant more often.

When the temperature drops too much in winter, the plant will show that it is stressed by turning the leaves yellow.

Whereas extreme temperatures may or may not contribute to the plant yellowing. Crown of Thorns is a tropical plant, and high temperatures may not have adverse effects.

Tips to Maintain Proper Temperature

  • Keep the plant away from air condition vents and drafty windows.
  • Use frost blankets during winter to protect the plant from extreme cold.
  • Bring the plant inside if the temperature drops too much during winter.

Should I Remove the Yellow Leaves?

The simple answer is: NO.

You shouldn’t randomly remove the yellow leaves from the crown plant. Why should you remove the yellow leaves if there is a hope of turning them back green?

Pruning yellow leaves
Pruning Yellow Leaves (Source: Pixabay)

First of all, you must find out the main cause of the yellowing.

Consider the following things before thinking about removing the leaves.

CausesShould You Remove the Yellow Leaves or Not?
Improper WateringRemove: If the plant has suffered from root rot.
Don't Remove: If the yellowing is at initial stage.
Inadequate LightDon't Remove the leaves as they can recover.
Lack of Proper NutrientsYellowing is the plant telling you to provide nutrients. Do not cut off the leaves.
Extreme Temperature FluctuationRemove: If moving them to suitable temperature doesn't revert the plant back to normal.

Apart from this, if you want to maintain the aesthetics of your plant, you can remove the yellow leaves. But remember, it is not compulsory.

If you decide to make the cut, cut at the end of the axil and avoid cutting the stem.

Make sure to use sterilized tools (knife and gloves), or you can just pinch them off.

Alert! These plants have thorns, be careful!

Watch this,

Conclusion

Crown of Thorns is an ideal plant for you that can be grown indoors and outdoors.

It doesn’t require intensive care and is easy to propagate. However, being said this, it still needs some primary care, mainly in the watering department.

So, take care of your plant, and be a proud plant parent. And follow our article for more updates.

Are you facing the yellowing of other plants? Read our articles on the yellowing of Stromanthe, Pilea, Asparagus Fern, AlocasiaHomalomena, and Sansevieria.

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