Life Amid the Palms

May 2024 - Welcome!

What's With Palm Fronds Yellowing?

6 Tips for You When Investigating Yellow Palm Leaves

Have you ever seen palms with yellow leaves? You want to be proactive in preventing this on palms you love.

Yellow leaves are botanically called chlorosis. Some tips can help to begin figuring out this Palm Tree Problem of leaf yellowing.

Seeing these yellowing fronds gets your attention!

Tip 1 for Palm Fronds Yellowing

What's your species of palm tree? Some palms do have yellow colors on stems & leaves - it's their normal. But some are especially vulnerable to conditions causing chlorosis. For instance weather:

• Is your plant a Palm That's Cold Resistant? Like A Coconut Palm is NOT! With a sudden hard freeze, certain Species Can be Affected.
• Extreme heat can cause chlorosis in palms originally from high elevations. Ceroxylon quindiuense, the Tallest Palm in the World, is like that.

Tip 2 for Palm Fronds Yellowing

Some palms love "wet feet" - roots sitting in watery soil. But most do not.

Some are sensitive to overwatering. Drought resistant palms won't do well in soggy soil. Root rot can result! Best to know your palm's watering needs.

Heading to Root Rot & Yellowing Fronds!

• Phoenix canariensis, the Canary Island Date Palm needs well-draining soil. Dense overwatered soil can cause yellow blotches on fronds.
• The Bismarck Palm is drought-hardy when established. Water it infrequently, yet deeply.

Nutrient Starvation!

A common reason for palm's yellow leaves is Nutrient Deficiency. Palms need certain macronutrients & micronutrients. To maintain green fronds.

Certain nutrient decreases can cause unhealthy palm frond yellowing.

Tip 3 for Palm Fronds Yellowing - Macronutrients

Palms need larger amounts of macronutrients than micronutrients. Which macronutrient deficiencies cause palm fronds yellowing?

• Nitrogen, mainly in Container Palms. Green color lightens, then turns yellow.

Nitrogen Deficiency Was Verified in This Coconut Palm

• Phosphorus affects oldest, lower fronds first, causing gradual yellowing.
  

• Potassium most commonly dwindles in landscape palms. Especially species like Areca Palms & Royal Palms.

Yellow Polka-Dots Aren't Decorative on This Palm Frond! Prime Indication for Potassium Deficiency.

• Magnesium lack is mostly found in Palms Growing in sandy soil & in containers. Distinctive wide yellow bands seen on edges of older leaves.
  

Palm Leaf Demonstrating Confirmed Magnesium AND Potassium Deficits

• Sulfur deficit hits youngest fronds first. Becoming totally yellow, or yellowing between veins.

Tip 4 for Palm Fronds Yellowing - Micronutrients

These "trace elements" are micronutrients because very small amounts are needed. Yet they're important.

• Iron shortfall is more common in potted palms than in landscapes.

Fishtail Palm has Verified Iron Deficiency. Showing Yellowing Between Leaf Veins.

• Manganese is typically inadequate in alkaline, sandy soils. Symptoms similar to Copper deficit.
• Copper sparsity is rare. Except for African Oil Palms growing in sandy soil.

May be lack of Manganese or Copper.
Newer leaves yellowing at tips, with brown stripes.
Gradually affecting the whole leaf.

Tip 5 for Palm Fronds Yellowing from Disease

Fungal Problems are difficult to diagnose. Fungus is often opportunistic, attacking when palms are weak from problems.

• Leaf Spot & Leaf Blight signs begin with frond's black/brown or yellow spots.

Spots become ringed with yellow borders. Eventually leaf is fully yellow.
Image Credit: Thailand Dept. of Agriculture

• Tar Spot Fungus begins with small angular black areas. Lining up with veins, surrounded by yellowing.

Soon the Entire Frond Will Turn Yellow

• False Smut isn't very worrisome. Tiny yellow spots may be on both leaf blade sides. Not necessarily harmful, but not pretty.
  

Tip 6 for Palm Fronds Yellowing for Disease

Three deadly diseases affect the meristem (growing point).

• Lethal Bud Rot affects youngest fronds first, easily moving to the bud. Caused by the Oomycete genus Phytophthora.

Coconut Palm Killed by Lethal Bud Rot. Also Called Heart Rot.

• Lethal Yellowing often targets Cocos nucifera. On affected species, like Trachycarpus fortunei, beginning with oldest fronds. Spreading upward, coloring leaves (some very bright) yellow.
• Hartrot or Fatal Wilt can begin with yellow tips on old leaves, quickly getting to newer fronds. Leading to many more symptoms. Eventually getting to the meristem.
• Sudden Wilt first affects fruit, then older leaves. Progressing to young fronds which initially turn yellow.

Takeaways for Yellow Frond Possibilities

Does this all sound scary? When yellow leaves develop on your palm. Approach it systematically.

• Know your palm's weaknesses, to evaluate potential causes

1. Which could be nutrient deficiencies (Give Palm Fertilizer), improper watering, disease, and/or environmental stressors.

• Regularly monitor your palm to get ahead of any discovered problem.
• Maybe soil testing or leaf lab tests will be needed, or reassessment for your watering schedule.

It all comes down to the exact needs & frailties of your palm & its environment. Use proactive watchfulness.

Til Next Time,

Karen & Bill of Mission: Palm Trees

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