Am i understanding this correctly ?

Honestly i have never seen a plant with a doughnut sized hole of nothing around it. Ive been to parks, garden centres, peoples gardens and online but have not seen this. I can do this tomorrow if this is best practice.

Does anyone have any pictures of this

When it rains, will rain water not accumulate in the hole and make the trunk wet ???

 

As I wrote earlier in the thread;

 

The only thing im planting new is lingonberry though im not 100% sure when they are arriving. I have been mulching and putting compost around my plants for years without a hole so i dont have the original containers any more but i can go around the base of all of them tomorrow.

 

If they've been fine for years then don't sweat it and carry on as you have been doing.
As for the Lingonberries (Vaccinium vitis-idaea) just plant them to the same depth as they have been planted already and then if you put any mulch or wood chippings just leave a gap around their stems so the mulch is not in contact with the stem.

 

hmm reading these comments have concerned me. I have a fig tree and the stem looked a bit green last week but i just scraped off the green part. It also produces suckers instead of figs so im wondering this may be the issue

 

It sounds to me as tho you're a bit of an insensitive bull in a china shop kind of gardener - suggesting glass against pests, plastic round trunks and so on.

Try and think more sensitively - how do plants thrive? what do they need to grow and be happy? Do some research and go gently. You can look up most plants that grow in the UK on the RHS website to find out what soil, aspect, temperatures they need and when to sow, plant, prune, harvest.

As for your fig, it's a Mediterranean plant that needs sunlight and copes with drought and heat so if your stems have green bits from moss or algae, something isn't right for it. Have a look a this - How to grow figs | RHS Guide