How to Care For a Bonsai Tree If It Looks Yellow

Yellowing foliage can be a sign of overwatering, lack of sunlight and disease.

Overwatering, root rot, poor air circulation and lack of sunlight are just some reasons why your bonsai may begin to yellow. Regardless of the reason, yellowing is a symptom of your bonsai's poor health and its way of saying it needs help immediately. Though not every ailing bonsai can be saved at this point, there are several steps that you can take to assist your bonsai in its healing process.

Things You'll Need

• Pruning shears
• Potting container
• Potting soil
• Sand
• Peat moss
• Fungicidal or insecticidal spray

Instructions

1. Inspect your bonsai thoroughly. Check the foliage for spots and bite marks, as these are signs of disease and insect infestation. Trim away any severely damaged, yellowed or eaten foliage with sharp, sterile shears. Remove any dead or damaged branches as well. Sterilize your shears between each cut to prevent spreading potential diseases throughout the tree.

2. Remove the bonsai from its container and inspect the root system. Look for mushy, reddened or stinky roots, which are a sign of root rot. Trim away dead, wilted, reddened and mushy roots with sterile shears. Remove all deadened and suffering roots, even if you have to remove more than one-third of the system.

3. Incorporate equal amounts of coarse sand, nutrient-rich potting soil and fresh peat moss. Mix the materials thoroughly to promote a well-drained, water-retentive soil mixture. Clean your bonsai's container with warm water and a mild soap. Dry the container with a clean cloth.

4. Affix wire mesh on top of each of the container's drainage holes to keep the soil and roots from exiting the container. Line the bottom third of the container with a layer of soil mixture. Center the bonsai in the container and fill it up with soil. Secure the bonsai's position by pressing the soil firmly around it.

5. Place your bonsai in the sink. Fill the sink with tepid water until it reaches just above the container's surface. Allow the bonsai to sit in the water until the bubbles stop rising to the surface. Unplug the sink and allow the bonsai to rest there until the water stops flowing from the drainage holes.

6. Place your bonsai in a warm location that has good air circulation. Keep it away from areas with direct temperature variations, such as heating vents and air conditioners. Select a sunny location that receives at least eight hours of full, indirect sunlight. Make sure that the foliage does not touch window panes, as the temperature variations could kill those leaves.

7. Avoid fertilizing your bonsai for several weeks while the bonsai re-establishes itself in the container. Treat the bonsai with a fungicidal or insecticidal spray if you found signs of disease or infestation. Dust the bonsai's foliage regularly to reduce the potential of fungal and bacterial diseases.

8. Allow the bonsai's soil to dry slightly between irrigations to avoid overwatering. Check the soil's moisture levels daily by feeling the soil. Place your finger about an inch into the soil and irrigate only when the soil feels somewhat dry. Water the bonsai evenly with tepid water. Use a watering can to complete the process and pour the water until the water flows from the drainage system.

References

• Bonsai for Beginners: Repotting Your Bonsai
• Bonsai4me: Bugs, Diseases and First Aid