Quote from Lee Garden Ninja on 19th April 2024, 4:07 pm

Hi @icas39

Thanks for your question about what's turning your Camellia leaves yellow and the flowers falling off.  There are many reasons why Camellias may get sick or damaged, but I think, looking at yours, it's a nutrient deficiency based on the colour of the leaves, and the recent flooding and rainfall may have something to do with it. All that water that has fallen over the past few months acts as a big flush to our soil, which can temporarily wash and flood out the nutrients that the soil is building up with its natural lifecycle of things dying, foliage falling and rotting into it, etc.

https://youtu.be/5BhGtCjT2TQ

So, I would immediately give your Camellia a good organic plant feed, both liquid and a good peat-free compost mulch, to help resolve it. I doubt the deficiency will kill the shrub, but it will boost it to help feed it.

To help other Ninjas, I'm also going to list the common reasons for Camellia leaves turning yellow and some treatments. Do let me know how you get on.

What causes camellias to turn yellow, and how to treat them?

Yellow leaves on camellia plants can indicate several underlying issues, so diagnosing the specific cause is crucial for effective treatment. Here's a detailed guide on what causes camellias to have yellow leaves and how to fix them:

• Overwatering or Underwatering: Improper watering is a common cause of yellowing leaves. Overwatering can lead to root rot, while underwatering can cause stress and nutrient deficiencies. Most enthusiastic gardeners drench their camellias too often which they don't like. Ensure camellias are never waterlogged, aim for the soil to dry out in between rain showers or your watering schedule. Adjust the watering frequency based on weather conditions and soil moisture levels.

• Poor Drainage: Camellias prefer well-draining soil. If the soil is heavy and poorly draining, it can lead to waterlogged roots and yellowing leaves. Improve drainage by amending the soil with organic matter such as compost or perlite. Planting camellias in raised beds can also help enhance drainage.

• Nutrient Deficiency: Yellow leaves may indicate a lack of essential nutrients, particularly nitrogen, iron, or magnesium. Conduct a soil test to determine nutrient deficiencies and adjust fertilizer applications accordingly. Choose a fertilizer formulated for acid-loving plants and follow the manufacturer's recommendations for application rates.

• pH Imbalance: Camellias thrive in slightly acidic soil with a pH between 5.0 and 6.5. High soil pH can lead to nutrient deficiencies and yellowing leaves. Test the soil pH and amend it as needed using sulfur or acidic fertilizers to lower the pH.

• Pests and Diseases: Certain pests, such as aphids, scale insects, or spider mites, can infest camellia plants and cause leaf yellowing. Inspect the leaves and stems for signs of pest infestation and treat them with insecticidal soap or horticultural oil if necessary. Additionally, fungal diseases like root rot or leaf spot can contribute to yellowing leaves. Remove and destroy affected plant parts and apply fungicides as directed.

• Environmental Stress: Environmental factors such as excessive sunlight, strong winds, or extreme temperatures can stress camellia plants and cause leaf discolouration. Provide adequate shade and protection from harsh weather conditions, especially during hot summer months—Mulch around the base of the plant to conserve soil moisture and regulate temperature.

• Transplant Shock: Transplanting camellias can cause temporary stress and lead to yellowing leaves as the plant adjusts to its new environment. Minimize transplant shock by watering the plant thoroughly before and after transplanting and providing optimal growing conditions.

I hope that helps.

Happy Gardening!

Lee