I have have been gone a month from my home and someone has been watering my plants. When I got home I thought since it had been very hot and dry that my geraniums had dried up...but there was still some green parts so I just started trimming the dry parts. However I see that there are like black holes and the inside of the stems are black...looks like fine wet soil. I can't see any pests. I looked online and well it doesn't look like stem rot but I'm not sure. Anyone know what it is and if it can spread to other plants?
Thanks in advance!!