Plant care guide
Rubber Plant Root Rot: Check Roots, Trim, Repot or Take Cuttings
Updated
Why does my Rubber plant have root rot?
Rubber plant root rot is caused by water molds and fungi such as Pythium, Phytophthora and Rhizoctonia, which take hold in mix that stays wet. Leaves yellow, wilt and drop, and the roots turn brown to black and soft. A plant with plenty of firm, pale roots left can be trimmed and repotted; one with a rotting stem base is better saved as cuttings.
What to do first
Unpot the plant and wash or shake off the old mix. Cut away every soft, dark root with clean shears, repot the firm roots in fresh, well-drained houseplant mix in a clean pot with drainage holes, and water only when the top of the mix has dried. If the stem base is soft, take cuttings from healthy stems instead.
A rubber plant with root rot can look like one that is simply overwatered, so you cannot confirm it from the leaves alone. Clemson Extension’s rubber plant factsheet says it usually follows a mix that drains slowly or overly frequent watering. If you are still at the wet-mix, yellow-leaf stage, start with our rubber plant overwatering guide. This page picks up once you suspect the roots themselves.
What causes it
The University of Florida’s Ficus disease guide describes three root pathogens on Ficus elastica:
| Pathogen | What UF describes | Favoured by |
|---|---|---|
| Pythium and Phytophthora | Yellowing leaves, wilting, root dieback, discoloured roots whose tissue sloughs off; dark lesions on leaves under wet conditions | Wet, saturated mix |
| Rhizoctonia | Young stems girdled and water-soaked at the base, collapsing; brown, web-like threads | Water-saturated mix |
UW–Madison Extension’s root rot article adds Fusarium and notes these fungi prefer wet soil. Some survive for long periods in soil or plant debris. That is why old mix and dirty pots matter.
Confirm it at the roots
Slide the plant out of the pot. On a large rubber plant this is a two-person job.
- Healthy roots are firm and light-coloured, as UW–Madison describes.
- Pythium rot leaves roots brown to black and soft. University of Maryland Extension’s root rot page says the outer layer pulls away from the core, leaving hair-like threads.
- Phytophthora rot turns root tips dark brown, then soft and mushy, Maryland notes.
- Rhizoctonia shows coarse, reddish-brown threads like spider webs.
- A bad smell and mushy roots point to rot, UW–Madison says.
Then press the stem at soil level. Clemson’s disorders factsheet notes that root and stem rot can girdle stems at or near the soil.
Decide: trim, propagate or discard
| What you find | Best move |
|---|---|
| A few soft roots, most firm, stem base firm | Trim and repot |
| Most roots soft, stem base still firm | Trim hard and repot, and take cuttings as insurance |
| Stem base soft or discoloured | Take cuttings from healthy stems; discard the rest |
Clemson says that if only a few roots are infected, remove them and repot in sterile soil. UW–Madison is blunt: the most cost-effective way to deal with a badly rotted plant is to throw it out. If the plant matters to you, trim and repot first, and take cuttings as a back-up.
Rescue steps
- Remove the old mix from around the roots. UW–Madison advises never reusing potting mix from an infected plant.
- Cut out every soft, dark root with clean, sharp scissors. Maryland’s repotting guide says to remove dead, brown roots. Wear gloves: Clemson notes the white sap may irritate skin.
- Clean your tools and pot. UW–Madison suggests disinfecting tools and pots with a bleach or alcohol solution. Maryland advises clean or new pots.
- Repot in fresh, well-drained houseplant mix, which Clemson recommends for rubber plants, in a pot with drainage holes. Maryland warns that products sold as “potting soil” are often too dense. UW–Madison advises against a layer of rocks at the bottom.
- Size the pot to the roots that remain, not to the old pot.
- Water once, then wait. Maryland says to water thoroughly after repotting, then hold off until the top of the mix dries.
- Keep the plant warm and in bright, indirect light. NC State Extension’s rubber plant profile asks for temperatures above 13 °C (55 °F) and protection from afternoon sun.
Should you use a fungicide?
UF lists fungicides for Ficus root rots, but its guide is written for commercial nurseries. UW–Madison does not recommend chemical fungicides for houseplants because of limited availability and cost. Drier mix, clean pots and fresh potting mix do the work at home.
If the plant cannot be saved
Clemson lists stem or tip cuttings and air layering for rubber plants. Maryland advises taking cuttings only from healthy tissue. Cut above any discoloured stem and check that the cut surface looks clean.
Judge recovery by firm stems and a new leaf at the tip. Brown spots on leaves are covered in our rubber plant brown spots guide. For everyday care, see our rubber plant care guide.
References
- UF/IFAS EDIS PP308: Ornamental Ficus Diseases: Identification and Control in Commercial Greenhouse Operations
- University of Maryland Extension: Root Rots of Indoor Plants
- UW–Madison Extension: Root Rots on Houseplants
- Clemson Cooperative Extension, HGIC 1510: Rubber Plant
- Clemson Cooperative Extension, HGIC 2251: Houseplant Diseases & Disorders
- NC State Extension Gardener Plant Toolbox: Ficus elastica
- University of Maryland Extension: Potting and Repotting Indoor Plants
How this guide was put together: University of Florida IFAS, University of Maryland Extension, UW–Madison Extension, Clemson Extension and NC State Extension guidance.