Euphorbia Trigonas With Stem Rot

Root and Stem Rot Causes

• Over-watering is the most common cause of root and stem rots. Roots left to sit in water will begin to decay, allowing bacteria and fungi present in the soil to invade and move through the plant. As these pathogens eat away at root and stem tissue, the movement of water to the above-soil parts of the plant is restricted, causing wilting and death.

Symptoms

• Initial symptoms are usually brown, mushy lesions of the stem or lower portions of the plant. As the disease progresses these lesions coalesce and the entire stem turns brown. Brown leaf spotting may occur if the pathogen moves through the vascular system to the upper parts of the plant. General yellowing and wilting are also common root and stem rot symptoms.

Re-potting

• If you have several stems growing in one pot, re-potting those less affected may save them. Carefully lift the plants from their container and discard those where the bottom is entirely brown. Inspect the roots of those that are not entirely brown. If more than half of the roots are rotted and mushy, discard that plant, it can be saved. If less than half of the roots have rotted, trim the rotted ones back to healthy tissue using clean scissors. Wear gloves, as euphorbias have toxic sap. Wash the old container with a solution of 1 part bleach to 9 parts water and rinse it thoroughly. If your old container lacks drainage holes and an overflow dish, purchase a new one with those specifications. Mix 50 percent peat and 50 percent coarse sand and fill the container with this mixture. Re-pot your euphorbia. Do not tamp the potting medium down or you might compromise its ability to drain. Water the mixture and allow it to settle. Once it has settled, add more potting mix, water again and allow it to settle. Repeat until you've filled the container to the desired height. Don't water again until half of the potting medium is dry.

Cuttings

• Succulents regenerate easily from cuttings and you may be able to save your euphorbia by cutting off the healthy tissue above the rot and planting it. Use a clean knife and cut well above the brown tissue. Wear gloves, as euphorbias have toxic sap. Dust the cut stem with a rooting hormone. These are commercially available, follow the manufacturer's directions when using them. Allow the cut end of the euphorbia to dry and form a callous before you plant it. If it is calloused, you'll have less chance of re-infection after re-potting. Once the callous has formed, stick the stem in a potting medium of 50 percent peat and 50 percent coarse sand. Keep the cutting moist, but not soaking. Rooting could take several weeks, so be patient.