Plant care guide
Anthurium Brown Spots: Read the Pattern, Then Fix the Cause
Updated
Why does my Anthurium have brown spots?
Brown spots on an anthurium come from leaf-spot disease, sun scorch, salt or fertilizer build-up, dry air at the edges, or cold water. The shape and position of the spot point to the cause: V-shaped edge lesions suggest bacterial blight, ringed spots with yellow margins suggest fungal leaf spot, and broad tan blotches suggest sunburn.
What to do first
Note where the spots sit and what they look like, then remove badly spotted leaves with clean tools, keep water off the foliage, and correct the light, feeding or humidity problem that matches the pattern.
Brown spots on anthurium leaves are a symptom with several possible causes. Some are infections that can spread. Others are injuries from light, salts, cold or dry air that stop once the conditions change.
Start by looking closely at one affected leaf. Where the brown starts, its shape and its edge tell you most of what you need.
Match the spot to the cause
| What you see | Likely cause | Source |
|---|---|---|
| Yellow, water-soaked patches at the leaf edge that turn into brown V-shaped wedges | Bacterial blight (Xanthomonas) | UF/IFAS PP292 |
| Small brown spots with yellowish margins, sometimes ringed, sometimes with tiny black dots | Fungal leaf spot | Clemson HGIC 2251 |
| Water-soaked spots, often with a yellow halo, drying reddish-brown | Bacterial leaf spot | Clemson HGIC 2251 |
| Broad, dry, tan blotches on the most exposed leaves | Sunburn | UF/IFAS EP159 |
| Bleached leaf centers with brown tips | Too much light | UF/IFAS EP159 |
| Brown tips, older leaves yellowing, crust on the mix or pot rim | Excess fertilizer or salt build-up | UF/IFAS EP159; Clemson |
| Browning along the edges in a heated room | Dry air | RHS |
| White or straw-colored patches after watering | Cold water | Clemson HGIC 2251 |
Bacterial blight: act quickly
UF/IFAS Extension’s anthurium disease guide calls bacterial blight probably the most serious anthurium disease. The first signs are yellowed, water-soaked lesions along the leaf margins. They grow quickly into dead, V-shaped lesions.
The bacteria enter through pores at the leaf edge and through torn or cut tissue. Systemically infected leaves may look bronzed, and plants can eventually wilt and die. UF/IFAS adds that the bacteria can infect other aroids, including Dieffenbachia, Aglaonema and peace lily (Spathiphyllum).
- Isolate the plant from other aroids.
- Keep the leaves dry. UF/IFAS notes that the bacteria swim across wet surfaces.
- Disinfect scissors between cuts if you remove leaves.
- If the plant is wilting with spreading lesions, discard it. UF/IFAS advises discarding infected plants in commercial settings.
Fungal and bacterial leaf spots
Clemson Extension’s houseplant diseases and disorders factsheet describes fungal leaf spots as small brown spots with yellowish margins, sometimes in a target pattern. Bacterial leaf spots are water-soaked, often haloed, and dry to reddish-brown in drier conditions.
NC State Extension notes that leaf spots on Anthurium andraeanum can occur with poor air circulation or wet foliage.
- Remove and dispose of spotted leaves.
- Water the mix, not the leaves. Stop misting a plant that has leaf spots.
- Give the plant more space and air movement.
- Clemson lists copper soap or Bacillus amyloliquefaciens sprays after removing infected parts. Follow the label, and spray outdoors in shade where the label allows.
Sun, salt and fertilizer injury
UF/IFAS Extension’s anthurium problem table links broad, dry tan blotches to sunburn. The RHS anthurium overview also warns that leaves scorch in direct summer sun. Move the plant to bright, indirect light.
UF/IFAS links brown tips with yellowing lower leaves to excess fertilizer. It advises leaching the mix, checking the roots and feeding less. Clemson adds that white or grey crust on the mix or pot rim signals salt build-up. Drench the pot with water to flush salts, and scrape off the crust.
Scorched or salt-burned tissue stays brown. Judge the fix by new leaves.
Dry air and cold
The RHS anthurium growing guide says leaves may brown at the edges when air is too dry, as in centrally heated homes. It suggests a tray of damp gravel, grouping plants or a bathroom spot. If leaf spots are already present, choose the gravel tray over misting.
Clemson notes that cold water or splashing leaves can leave white or straw-colored spots. The RHS warns that anthuriums can be damaged by temperatures of 10 °C (50 °F) or lower, or by cold water. Use water at room temperature.
When to escalate
Spots that spread fast from the leaf edges, a bronzed cast across the plant, or wilting in moist mix suggest an infection rather than an injury. Isolate that plant first. Wilting in wet mix can also mean root rot, so check the roots.
Our general guide to brown spots on houseplant leaves covers other genera. The anthurium hub collects our other anthurium pages.
Related guides
Other anthurium problems we cover: watering frequency, overwatering, spider mites treatment, common problems, not blooming.
References
- UF/IFAS Extension: Anthurium Diseases, Identification and Control in Commercial Greenhouse Operations (PP292)
- UF/IFAS Extension: Cultural Guidelines for Commercial Production of Interiorscape Anthurium (EP159)
- Clemson Cooperative Extension HGIC: Houseplant Diseases & Disorders (HGIC 2251)
- NC State Extension Gardener Plant Toolbox: Anthurium andraeanum
- RHS: How to grow anthuriums
- RHS: Anthuriums
How this guide was put together: UF/IFAS Extension, Clemson Extension, NC State Extension, and RHS guidance.