Calla - recover from root rot

Question

I have a calla lily, which i seem to have overwatered. The leaves turned yellow and started to come off at their base. I repotted today and noticed, that almost all the roots were rotten. I removed the rotten roots, and the rhizome seems to be healthy, so I cleaned it from soil. However there aren't too many healthy roots, and the foliage is still large. How can I save the plant?

I see my options as follows:

• repot: since there aren't too many roots, it can't take up much water, and because of the large foliage, it is going to evaporate a lot. I'd probably need to reduce foliage. But I fear, that root rot is going to come back again.
• cut off leaves, dry rhizome and store until next year: the plant might not have had enough time to store enough energy
• put into water and wait until it regrows some roots, then pot: i have successfully saved some alocasias this way. But I'm not sure it works with calla's.

All the info i found about recovering from root rot online, seems to be clickbait.

Answer 1

The remaining roots look white and sturdy, however the rhizome on the right side looks a different colour to the rest on the left side. Only you can say if it is less viable than the lighter section (touch and smell)

I might be tempted to use a sharp sterile blade and slice the rhizome in 2 (along the 2/3rd line delineated by what seems to be a white root) and put each clump into separate glasses of water, changing the water once a week or earlier if the water goes cloudy. If the water goes cloudy in one glass and not the other, at least you have the chance of saving one part of the plant.

How and when you determine whether you return these plants back into a well draining gritty substrate or attempt semi-hydroponics in leca is up to you depending upon the hopeful success of sustaining heathy roots and rhizome(s).

For the second stage, the scientist in me would be driven to try one in a gritty well draining substrate and one in leca+water for a further test as to their longer term prospects in semi-hydro. I have both peace lilies and sansevieria (with a healthy rhizome) growing well in semi-hydro for the past 12 months and would be interested to know if this species could also succeed in this medium.