What is Crown Rot?

Mary McMahon
Mary McMahon

Crown rot is a disease which affects many different types of plants. Plants afflicted with this disease experience rot around their stems, in the area where the stem joins the root. Typically, crown rot is fatal, although it can be treated in some cases if a gardener is willing to put in some extensive efforts. As with many other plant diseases, prevention is easier than curing.

Potato plants can be affected by crown rot.
Potato plants can be affected by crown rot.

Several different organisms can cause crown rot. One of the most famous is Phytophthora, an organism which is often mistakenly referred to as a fungus, although it is actually a protist. These nasty garden visitors were responsible for the infamous Irish Potato Famine, and they continue to wreak havoc on plants all over the world.Fusarium fungi can also cause crown rot, as can several other fungal species, and sometimes the condition is linked to bacteria or nematodes.

The Phytopthora protist was responsible for the Irish Potato Famine.
The Phytopthora protist was responsible for the Irish Potato Famine.

The “crown” of a plant is the point at which the stem and roots join. It is a critical part of the plant's anatomy, and when a plant is attacked by crown rot, the symptoms show up very quickly. Typically, the leaves start to discolor, wither, and die off, and the whole plant may droop. Occasionally, the visible part of the stem above the ground may acquire a dark color, a slick texture, and a mushy feeling. Eventually, the plant will die off altogether, because the crown rot effectively separates the plant from its roots.

When crown rot starts to develop, the best thing to do is to discard the plant and the soil around it. If the plant is valuable or particularly beloved, treatment can be attempted by removing the plant from the soil, washing the plant and its roots, trimming away obviously dead material, and replanting it in sterile soil. Applying a fungicide may sometimes work, if a fungus is causing the crown rot. The plant should also be isolated so that it cannot infect other plants.

Prevention of crown rot starts with using good quality, sterile soil for new plantings, so that plant pathogens cannot be passed around the garden. Plants should also be given a stable supply of water which meets their needs, and gardeners should avoid over watering or allowing plants to dry out totally, as these conditions can both promote the growth of unwanted organisms in the soil. Maintaining healthy soil and keeping plants unstressed will also help to prevent crown rot and other diseases.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


thank you for the site. it helped heaps.


@letshearit - That's fantastic advice, which I will be following from now on. Sadly we didn't know how easily this spreads, and just one African Violet with crown rot managed to decimate most of the plants it shared space with.


If you are a fan of beautiful plants and like to keep African violets, begonia or cacti, you should be aware that these plants are extra susceptible to crown rot.

Too much moisture is one of the main causes of crown rot, so you have to make sure the soil is just getting dry before you water your plants.

Plants like African violets have their crown very close to soggy ground, so you must take care to make sure they aren't overly saturated. A good idea if you over water is to gently pat the flowers, leaves and stem dry with a paper towel and hope for the best.


If you have a greenhouse and enjoy caring for your plants making sure that they are not exposed to crown rot is vital. Often you will bring in plants from outside sources, but as a precaution, they should under go a bit of a quarantine period before adding them into your main collection.

It is a good idea to have a separate room where you can keep new plants for the first week or so, to make sure that they don't develop any unusual symptoms.

I usually transplant new additions right away and make sure they are as clean as possible.

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