Devon,
United Kingdom 
Two years ago, I had a red oak taken down because it had oak bracket. The remaining stump is about 4' diameter. Recently, half the stump crumbled away and I expect the other half do so. Underneath it's just a massive hole which surprised me. What should I do with it? Could I fill it with soil and plant in it?
13 Dec, 2020
Answers
Yes, obviously the oak had to be taken down. Good move because it rotted out and would have fallen. You can certainly fill it and plant whatever you want.
13 Dec, 2020
Thankyou Sbg and Bathgate for replying to my question. It's quite shady so I was thinking of ferns.
13 Dec, 2020
they should be fine MB, do you like Epimedium? they'd do well there too.
13 Dec, 2020
I love Epimedium! Thankyou SBG.
15 Dec, 2020
yes fill it will soil but plant plants that are resistant to bracket fungi. I'd go for herbaceous perennials rather than any shrubs/trees.
13 Dec, 2020