it's growing on the root ball of my chocolate mint and also growing on the outside of the terracotta pot it's growing in. Plant is vigorous and healthy, neither too dry or too wet. Nothing crawling around- no root aphids; substance is almost waxy which suggests this but I don't think it is esp with it growing on outside of pot. Doesn't look like crown rot either
Googled till eyes are googly .HELP...I loves me chocolate mint
No comments on how I should be wearing gloves or using handcream- my 52 year old careworn hands are beyond redemption
Hmmmmmm, it looks like some kind of fungus or slime mould. My guess - and it is just a guess - is that it's caused by the damp soil that mint likes and something in the compost that is still being broken down - sometimes I find similar white mould in the middle of sacks of compost. It doesn't seem to be damaging your plant, so it's not feeding off that. I wouldn't worry too much about it - you could always cover the bottom with a fresh load of compost to make it look more attractive.
Thinking about this - the challenge is that mint likes it fairly damp, but so does mould. I'm wondering if one thing you could do is to improve drainage a little in the pot - not to make it alpine-like or anything like that, but just a bit to get rid of any compaction issues and loosen it up a little. I'm saying this on pure gut instinct, not on knowledge at all so it might be a totally stupid idea. . Also, getting it somewhere with some air movement may help.
The main thing is whether it's affecting the plant, and your mint looks strong and healthy, which is a relief. It does look alarming, but perhaps it's not as much of a concern as it appears?
I had a quick google and there are people sprinkling cinnamon and athlete's foot powder (!) on the soil. The former sounds like it might be worth a try??
There is a white fungus that grows through bark chips and those chocolate bean shells you can use as mulch that is actually benficial- I only know this as I read it on the chocolate bean bag and then saw it in barkchips too. Maybe take some cuttings as back up? Don't know about chocolate mint but ordinary mint you can just leave a stem in a glass of water and it will root- (apologies if I'm teaching you to suck eggs- particularly as I'm a beginner! )