I have a plant that I received from someone a couple of years ago. I don't...

Asked October 18, 2015, 9:43 PM EDT

I have a plant that I received from someone a couple of years ago. I don't know what it is. It used to be graphed with a coral cactus. Last winter I found aphids on it and paniced. I threw it away so it wouldn't infest my roommates plants. The next morning I had second thoughts and brought it into another area of the house. It lost its leaves and the "trunk" shriveled. After a couple of months I found rot and cut it out. This summer I set it outside and it started to sprout leaves again! Now I notice it has more rot about halfway up the stalk. It's about 1/3 of the way around the stalk and I think if I cut it out there may be nothing left. What should I do??

Olmsted County Minnesota fungal disease euphorbia

5 Responses

According to the International Euphorbia Society, the only cure for rot is to cut off the still unaffected parts of the plant, but generally this only works during the early stages of the disease.

The salvaged portions might be propagated but growers say it's usually difficult to root cuttings taken in the fall.

Learn more here:
http://msue.anr.msu.edu/news/secrets_to_success_when_propagating_succulent_plants

So should I cut it through the thick stalk or should I cut off the small piece at the top. I'm not sure if the small piece is a bundle of leaves or a propogation.

This is indeed called a Euphorbia as my colleague Bob noted in his earlier response. Euphorbias and cacti are often confused; however, Euphorbias have a milky white sap and cacti have a clear sap. Note that the Euphorbia sap can cause dermatitis, so use gloves when working with the plant.

Your plant appears to be fine. The blackened top of the stem is residual of the earlier stem dieback. I don't see any other blackened areas on your plant.

You may be overwatering the plant. The soil may also be too rich for the plant, holding too much water and essentially causing root rot which may be recognized by the stem rot. I recommend re-potting the plant using a cactus soil blend (you can buy this in a garden center) and a clean pot with good drainage. While you have the plant out of the pot, examine the roots and cut off any that are soft and rotten (root rot). The remaining roots should be creamy / white and firm.

If you use the same pot, wash the pot well in hot soapy water inside and out.

Once re-potted, water this plant only when the soil is completely dry. Keep it in a bright sunny window.

You can reply directly to this email with any additional questions and I will receive it.

Oh that is good news! Thank you! I just want to clarify with a better picture of the area I think is rot. Do you still think this is not rot and it will be ok with just a repot into better soil?

The rotted area is not large. It may heal or form a callus. Or the damage may be irreversible and the plant breaks off at that point. It may resprout leaves as it did at the top of your current plant. Your options are to throw it away now and get a new plant, or repot it and see if that helps. If the plant is important to you, then I would repot it.