Plant care guide
Chinese Evergreen Root Rot: Treatment and the Peroxide Question
Updated
Why does my Chinese evergreen have root rot?
Chinese evergreen root rot comes from mix that drains slowly or is watered too often, especially in a cool room. Leaves droop and yellow while the mix is damp, stems may soften at the soil line, and the roots turn brown to black and mushy. No extension guidance we found recommends hydrogen peroxide; the published treatment is trimming, fresh mix and less water.
What to do first
Wear gloves, unpot the plant and cut away soft, dark roots. Repot in fresh soilless mix in a clean pot with drainage holes. If the stems are soft at the base, root healthy tip cuttings instead. Water again only when the top 2.5–5 cm (1–2 in) of mix is dry.
Clemson Extension’s Chinese evergreen factsheet calls Aglaonema one of the most durable houseplants. When one collapses, the roots are a common reason. Clemson says root rot usually results from a soil mix that does not drain quickly or from overwatering. NC State Extension’s Aglaonema profile agrees that root rots can occur with overwatering.
Is it root rot?
Look at the plant and the mix together:
- Leaves drooping or yellowing while the mix is still damp days after watering.
- Stems soft, dark or mushy at the soil line.
- Roots brown to black and soft, with an outer layer that slides off.
- A sour smell or fungus gnats around the pot.
University of Maryland Extension’s page on root rots of indoor plants describes the roots. It notes that Phytophthora can also turn the lower stems black, brown or mushy, which leads to lower leaves yellowing and dropping. Clemson’s diseases and disorders factsheet adds that stems may be girdled near soil level by a ring of brown or black tissue.
Drooping in dry mix, or after a cold night, is a different problem. Our Chinese evergreen drooping guide sorts out thirst, chilling and low light.
Does hydrogen peroxide help?
We could not find extension guidance that recommends hydrogen peroxide for Aglaonema root rot, or for houseplant root rot in general. Clemson, Maryland and Wisconsin all give the same treatment: remove rotted roots, use sterile mix and clean pots, and water less.
University of Wisconsin–Madison Extension’s page on houseplant root rots goes further. It does not recommend chemical fungicides for houseplant root rots, because few products are available to home growers and those that are tend to be expensive. Clemson says fungicides probably cost more than a new plant. Wisconsin’s main advice is short: reduce soil moisture.
Whatever you pour into the pot, the roots are still sitting in wet, old mix until you change it. Start there.
Treatment
- Wear gloves. NC State says Aglaonema contains calcium oxalate crystals, and touching the sap can cause dermatitis. Clemson notes the leaves can be toxic to dogs and cats.
- Unpot and remove the old mix. Wisconsin warns against reusing mix or drainage water from a rotted plant, because both can carry root rot fungi.
- Cut out rotted roots. Clemson says that if only a few roots are infected, cut them out and repot in sterile soil.
- Repot in fresh mix. Clemson recommends a standard soilless mix with extra humus, in a container with drainage holes. Virginia Cooperative Extension’s watering guide warns that an oversized pot holds roots in a zone that stays too wet.
- Clean the pot. Clemson suggests scrubbing and rinsing it in one part bleach to nine parts water.
- Water once, then wait. Clemson’s two-finger test works well here. Push two fingers into the top 5 cm (2 in). Dry means water. Cold and damp means do not.
If most roots are dark, soft and dead, Clemson says discarding the plant is the better choice. Before you do, check the tops. Maryland advises taking cuttings only from healthy tissue, so cut above any soft stem. Clemson lists stem and tip cuttings for Chinese evergreen, and our Chinese evergreen propagation guide walks through them.
Prevent it
- Water by the mix, not the calendar. Clemson says to water when the top 2.5–5 cm (1–2 in) is dry.
- Use room-temperature water. NC State and Clemson both advise against cold water.
- Water less in winter. NC State says Aglaonema prefers reduced watering then. Virginia’s guide notes plants by a cold window use less water.
- Keep it warm. Clemson gives 20–27 °C (68–80 °F) as the best range and says the plant is sensitive to chilling below 10 °C (50 °F).
- Empty the saucer. Virginia warns against leaving pots in water for more than 60 minutes.
For general care, see the Chinese evergreen care guide. Our root rot guide covers rot across houseplants.
References
- Clemson Cooperative Extension HGIC 1500: Chinese Evergreen
- NC State Extension Gardener Plant Toolbox: Aglaonema
- Clemson Cooperative Extension HGIC 2251: Houseplant Diseases & Disorders
- University of Maryland Extension: Root Rots of Indoor Plants
- University of Wisconsin–Madison Extension: Root Rots of Houseplants
- Virginia Cooperative Extension: Properly Watering Container Houseplants (SPES-804)
How this guide was put together: Clemson Cooperative Extension, NC State Extension, University of Maryland Extension, University of Wisconsin–Madison Extension and Virginia Cooperative Extension guidance.