you can cut the leaves. remove rotting part, let it dry in room temp 3-4 days, then plant it, (S. trifasciata and all Sans that I know of can be propagated by leaves cutting, rearrange leaves in pots as you like. water sparingly, only when medium dried. Room temp bright light but nut direct sun for now. treat like succulent. avoid too much watering. most likely you will end up success.

Cynthia, as Tyler above points out, it's reverting to normal growth. It can easily be grown on its own roots, but was likely grafted to accelerate its growing (which it has done splendidly). Be careful of this plant's sap - depending on your sensitivity, it can be an irritant or worse to skin, and definitely keep it away from all mucous membranes, If you're going to trim it for cuttings (or to take the load off of that graft), have some warmish water to daub the cuts in - that will slow down the milky latex bleeding.

It does look like an oregano plant and I thought that initially, but I really don’t smell anything when I bruise the leaves. Plus, I’ve never grown oregano in that garden. Yes, Lamium!! I purchased several varieties of Lamium years ago and planted in my gardens because it doesn’t take over and is not as invasive as some other ground covers.

I really don’t think they’ll appreciate being transplanted at this stage. Maybe with next year‘s seedlings.