Why Are My Rubber Tree Leaves Curling | How to Fix It

Rubber tree plants, Ficus elasticas, are quick-growing trees that are native to the fig family of tropical Asia. 

During the early 1900s, they were used to make an inferior form of rubber. However, today, the rubber tree makes a great houseplant thanks to its low-maintenance and adaptable nature.

In spite of its forgiving qualities, rubber trees can be susceptible to leaf curling issues that can quickly lead to plant death. This article breaks down the causes of specific symptoms and provides solutions to those problems. 

Why Do Rubber Plants Leaves Curl?

Environmental factors including soil moisture levels, nutrient availability, climate, and fungal infestations are the most common causes of leaf curling in rubber tree plants.

Leaf chlorosis, or yellowing of leaves, often comes before leaf curling and can be the first sign of problems with your rubber tree, so watch for any color changes from your rubber plant’s normally glossy, deep emerald-green leaves. 

Causes of Rubber Tree Leaves Curling

The following symptoms will help you determine the cause and solution to your rubber plant’s curling leaves. 

Curling Upward

When rubber plant leaves curl upwards, it is often a sign of a lack of soil moisture from underwatering and is the rubber plant’s attempt at limiting transpiration and further water loss. 

If severe, then wilting, leaf chlorosis, and crisping of the leaf edges will likely follow leaf curling due to nutrient deficiencies caused by root death. 

How to Fix:

Promptly water with enough liquid to fill the container the rubber plant is in and allow it to drain. Repeat daily for 2 – 3 days or until you see it start to recover. 

Then, water every time the top 2 inches of the soil is dry, which is usually twice per week during the warm months and only once per week during the colder months. 

Curling Downwards

The downward curling of rubber tree leaves is a sign of saturated soil caused by overwatering. It’s often coupled with yellow, pale, wilted leaves and stunted growth due to nutrient deficiencies caused by root rot.

How to Fix:

Remove any water from the catch tray and allow the soil to dry before watering again. 

If your rubber tree’s soil often retains too much moisture, then transplant it into a well-draining soil mix like the following: 

  • 4 Parts Sedge Peat 
  • 1 Part Sand 
  • 4.2 kg/m3 of Dolomite
  • 1.8 kg/m3 of Calcium Carbonate (CaCO3)
  • 0.6 kg/m3 of a general micronutrient granule fertilizer

Curling and Yellowing

Nutrient deficiencies are the most common cause of curling and yellowing leaves on rubber tree plants. 

  • Nitrogen – Lower leaves will begin to yellow and curl. Browning and leaf drop will follow. 
  • Potassium – Symptoms include interveinal yellowing of the entire plant, followed by leaf curling and browning leaf edges. 
  • Phosphorus – Older leaves will begin to curl and distort. This is usually coupled with leaf yellowing and browning. 
  • Calcium – This is where leaf edges will curl and be accompanied by a blackened leaf margin. Tissue death and severely stunted growth can also result. 

How to Fix:

The University of Florida suggests using a slow-release granule fertilizer, such as Osmocote, with an N-P-K ratio of 18–3–10 at an application rate of 27g per 30cm container every 6 months. 

If your plant is in need of a quick fix due to severe nutrient deficiencies, I recommend feeding it with a tropical houseplant-specific liquid fertilizer with a low N-P-K rating of 1–0.5–1 while waiting for the granules to take effect. 

Curling and Browning of Top Leaves

Curling leaves and irregularly shaped browned scorched spots indicate damage from too much direct sunlight.

All rubber plant varieties are tropical understory species that are best grown in shade to partial sun. While many larger rubber trees can survive full sun conditions, their leaves are paler and less glossy than those thriving in shaded conditions. 

More miniature single-stemmed rubber tree houseplants are unlikely to survive in full sun conditions.

How to Fix:

Relocate your rubber tree where it will get around 7 hours of bright, indirect sunlight. Water thoroughly and prune any dead leaves once the plant has recovered.

Leaves Curl and Drop 

Temperatures below 55.5 degrees Fahrenheit and above 100 degrees Fahrenheit can cause leaf curling, followed by massive leaf drops if improper conditions persist. 

How to Fix:

Keep your rubber tree at least 9 feet away from heat sources, air conditioning units, or drafty windows and doors, especially during the colder months. 

If damage has occurred, move your plant to a more suitable position and feed it with a low N-P-K liquid fertilizer while it recovers. To limit potential stress, prune no more than 30% of its dead leaves at any time. 

Leaves Twisting Upwards with Leaf Spots

The upwards twisting of your rubber plant’s leaves with the presence of numerous yellow and black spots on the upper side of the leaves and reddish-brown rusty spots on the underside of the leaves indicates an infection by the phytopathogenic fungus, Cerotelium fici, or fig rust. 

How to Fix:

While the best control is prevention, studies have shown that the fungicide Mancozeb applied at a rate of 0.2% is the most effective at controlling fig rust infections. Always use as directed. 

Prevention of fig rust infections includes isolating new plants, watering without wetting the leaves, and pruning for better air circulation.  

Curling With White Residue

Powdery mildew commonly causes white powdery residue on the entire leaf and curling of leaf edges, typically in the upwards direction. It commonly starts on the youngest leaves and quickly progresses across the entire plant if left untreated.

How to Fix:

Spray with a pre-mixed, all-natural, essential oil product that contains neem and lemongrass. This works great as a powdery mildew preventive as well. 

Curled Green Leaves 

Curled leaves that are green in color and small in stature are just the rubber plant’s new growth. As rubber trees develop new leaves they grow in a tight curl and will unroll as they continue growing. 

How to fix:

This is a natural process that doesn’t need rectifying, but if you notice new growth on your rubber plant, then you could supplement it with a low ratio N-P-K liquid fertilizer to prevent nutrient deficiencies during times of heavy growth.

For more information about house plants with curling leaves, here’s a link that may be of interest: 8 Causes of Pilea Leaves Curling

Citations

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Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.