Can I save a plant with root rot?

If the damage is minor, you can trim away the mushy roots and repot the plant in fresh, dry soil. If the majority of the root system is black and slimy, it is best to start over.

Does this plant need a lot of water?

No, it is quite drought tolerant once it is established. It prefers to stay on the drier side.

Prostrate knotweed: root rot, causes and fixes

Check these first

Feel the soil 2 inches deep to see if it is soggy.
Check that the pot has holes at the bottom.
Smell the soil for any signs of decay.

Likely causes

Overwatering
Most likely
How to tell: The foliage may look wilted or yellow even when the soil feels damp. You might notice a musty smell coming from the soil surface.
What to do: Stop watering immediately and let the top 2 inches of soil dry out completely. If the soil is heavy, mix in some perlite or sand to improve drainage for next time.
Poor Drainage
Possible
How to tell: Water pools on the surface for a long time after you water. The plant looks stunted and fails to grow even in full sun.
What to do: Ensure your pot has drainage holes at the bottom. If planting in the ground, choose a spot that does not collect standing water after rain.

Root rot in other plants

Find out what's wrong with your prostrate knotweed

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

When to worry

If the stems feel mushy or turn black at the base, the plant is likely too far gone to save. It is normal for the plant to look slightly tired if it has been in a period of heavy rain.

Stopping it coming back

Only water your knotweed every 7 to 14 days and ensure the soil dries out between sessions.

Prostrate knotweed: root rot? Check yours with a photo

Every plant is a little different. Take a photo of your prostrate knotweed and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

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Questions people ask

Can I save a plant with root rot?: If the damage is minor, you can trim away the mushy roots and repot the plant in fresh, dry soil. If the majority of the root system is black and slimy, it is best to start over.
Does this plant need a lot of water?: No, it is quite drought tolerant once it is established. It prefers to stay on the drier side.

Why is my prostrate knotweed showing signs of root rot?