Although the mother plant has been healthy for a couple of years, all of a sudden it started to droop. There seem no evidence of bugs. What could be causing this? The roots look good.
Certified GKH Gardening Expert
That soil appears to be over-wet, which can cause this. This is usually the most likely culprit. Make sure to let the soil dry slightly between waterings, and do not let it sit in water.
It might be wise to try and root another cutting just in case the plant becomes un-salvageable. Make sure when you are trying to root these that the soil has only a very small nutrient content, as heavy nutrients will actually prevent rooting. After they have rooted you can apply a more rich soil, or feed.
Alternatively, Temperatures in the low 60's can cause this. These are not at all cold hardy.
This article will guide you on the care of these plants: https://www.gardeningknowhow.com/edible/herbs/scented-geranium/mosquito-citronella-geranium-plant.htm