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Plant problems

Root rot in plants: causes and fixes

Root rot starts when roots sit in soil that stays wet, run short of air and begin to decay, often helped along by fungi in the soil. Watering too often and a pot that doesn't drain are behind most cases. Above the soil it can look like thirst, with drooping, yellowing leaves, so the roots are where you find out for sure.

root rot on a plant
Photo: Ninjatacoshell, CC BY-SA 3.0

Check these first

  1. Feel the soil. If it stays wet for days after watering, the roots aren't getting the air they need.
  2. Check the pot. Make sure it has a drainage hole, and that no water is sitting in the saucer or a decorative outer pot.
  3. Slide the plant out and look at the roots. Healthy roots are firm and white or tan; rotten ones are brown or black, soft, and often smell bad.
  4. Look at the base of the stem. A dark, soft stem at soil level means the rot has spread upward.

Most common causes

The causes our guides to 1,502 plants name most often.

  1. Poor drainage

    Named for 1,420 plants

    How to tell: Water sits on the surface of the soil for a long time after watering.

    What to do: Repot the plant into a well draining potting mix with added perlite. Ensure the pot has adequate drainage holes at the bottom.

  2. Overwatering

    Named for 1,371 plants

    How to tell: The leaves turn yellow and the base of the stems feels mushy or soft.

    What to do: Stop watering immediately and let the soil dry out completely. If the plant is in a pot, repot it into fresh, well draining soil and trim away any black, slimy roots.

  3. Waterlogged soil

    Named for 64 plants

    How to tell: The plant wilts despite the soil being wet, and the base of the stems looks dark or mushy.

    What to do: Remove the plant from the pot and trim away any black, slimy roots. Repot into fresh, well draining soil and reduce your watering frequency.

  4. Phytophthora root rot

    Named for 16 plants

    How to tell: The plant wilts even when the soil is moist, and the roots look dark, mushy, or brittle instead of firm and white. The leaves may turn dull green or brown before falling off.

    What to do: Improve drainage immediately by amending the soil with organic matter or moving the plant to a raised bed. If the roots are mostly black and mushy, the plant is likely beyond saving.

  5. Stagnant water

    Named for 12 plants

    How to tell: The water in your tray smells foul or looks murky. The base of the plant may appear mushy or discolored.

    What to do: Empty the water tray immediately and rinse it thoroughly. Flush the soil with fresh distilled water to clear out any buildup.

  6. Phytophthora infection

    Named for 10 plants

    How to tell: The tree shows sudden wilting and thinning foliage despite moist soil. You might see dark, oozing lesions on the lower trunk.

    What to do: Improve soil drainage immediately by adding organic matter or creating a mound. Avoid watering near the trunk base and keep the area around the roots clear of mulch.

Not sure what you're seeing? Try the free photo health check.

Plants most prone to this

Our guides rate it likely for 741 plants. Here are 48 of them, A to Z.

Find your plant

Every plant guide links to its own pages on that plant's problems. Find yours in the A to Z:

Other symptoms

Pest, disease and disorder guides

How often do the guides name each cause, across every symptom? See what goes wrong with plants, counted.

The causes on this page are drawn from our plant guides, which are generated with AI from each plant's care profile. They are general information, not horticultural advice. Read about how we build these guides.