|Have a geranium with white flowers. last week noticed that stem close to root was shriveling. today when i cut the stem to take a cutting, the entire interior was black. i managed to get just one cutting from the tip with 2 leaves still intact with green stem. How can i save this piece of plant. Should i let it root in water or soil. Is this a disease - stem rot. How can i prevent it in future.|
|Things don't sound good for your geranium, or for the cuttings you took. Stem rot is commonly called "black rot" by growers. The vascular system of infected stems darkens and eventually becomes black. This commonly occurs two to four weeks after infection. As bacteria rot through the stem, infected tissue becomes dry, black and shriveled. If the stem is cut at the advancing edge of the rot, yellow bacterial ooze often appears on the cut surfaces. Plants may possess several blackened branches in addition to the main stem. Infected branches usually become completely defoliated except for small clusters of leaves at the tips. Blackening may also progress down the stem and affect the roots; however, rotting of root tissue rarely occurs. Some infected plants may seem to recover and produce branches that appear to be healthy but this new growth nearly always becomes infected and dies. Infected cuttings typically fail to root. Instead they develop rot that gradually moves up the stem. I guess the bottom line is that although your cuttings look healthy, I suspect they, too, are infected with the bacteria. It would be best to toss everything out and start again.
Stem rot can be avoided if you are careful not to over water or over fertilize. Allow the soil to dry out slightly between waterings, keep water off the leaves, make sure air circulation around the plant is adequate and resist feeding your geraniums more than once a year.
Wish I better news for you.