Root Rot in Chinese Evergreen — When Overwatering Becomes a Crisis
Chinese Evergreen (Aglaonema commutatum (and related cultivars))
Symptoms
- yellowing leaves that do not respond to watering corrections
- soil that remains wet for 2+ weeks after watering
- a sour or fermented smell from the soil
- the plant feeling loose or wobbly in its pot
- roots that appear brown, soft, or slimy upon inspection rather than pale and firm
Causes
Pythium or Phytophthora in peat-based mix kept too moist
Chinese Evergreen is frequently sold in heavy peat-based or cheap composted mixes that hold moisture for very long periods. This soil is appropriate for short-term nursery conditions where plants are watered daily, but it is problematic in a home setting where watering is less frequent. Peat-based mix can develop anaerobic conditions in the lower pot within days of watering, creating the oxygen-depleted, moist environment that Pythium and Phytophthora require. The rhizomatous root system of Aglaonema is relatively susceptible once these pathogens establish.
Watering before the soil has adequately dried
Chinese Evergreen's tolerance for dry periods is better than many owners expect, which means the correct protocol — waiting until the top 50–75% of soil is dry — extends watering intervals significantly. Growers who water when only the top inch is dry are consistently overwatering this plant, particularly in winter when growth slows.
How to Fix It
- 1
Unpot the plant and shake loose as much of the old potting mix as possible. Do not be rough with the roots — Chinese Evergreen roots can be fairly brittle.
- 2
Rinse the roots under a gentle stream and run each one between your fingers rather than just looking — Aglaonema's rhizomatous roots are brittle enough that a healthy one snaps cleanly under light pressure, while a rotted section simply squashes flat without resistance. Cut every section that squashes rather than snaps back to firm tissue with sterile scissors.
- 3
Dust the freshly cut rhizome and root ends with powdered sulfur or activated charcoal before they go anywhere near soil again, since Aglaonema's rhizome is where this plant stores its real reserves and a reinfected cut there threatens the whole root system, not just one section.
- 4
Repot in fresh, well-draining mix: 50% quality potting soil + 30% perlite + 20% bark. Aglaonema's compact crown doesn't need much room to work with, so match the new pot to the trimmed root mass rather than sizing up for future growth. Avoid peat-heavy mixes.
- 5
Water very lightly to settle roots. Do not water again until the top 75% of soil is dry. Keep in warm conditions (70°F+) to support root regeneration.
Prevention
- Replace nursery peat-based mix within 3–6 months of purchase with a well-draining mix
- Give the pot a real dry-down between waterings — roughly the bottom quarter still slightly moist is the point to water again, not the moment the surface looks dry
- Ensure drainage holes are present and not blocked
Quick Summary
| Plant | Chinese Evergreen (Aglaonema commutatum (and related cultivars)) |
|---|---|
| Category | Disease |
| Likely causes | Pythium or Phytophthora in peat-based mix kept too moist, Watering before the soil has adequately dried |
| Fix steps | 5 steps — see above |