Depends on what sort of soil you have. In other words, how deep your top soil is, this will affect the depth of the roots and what you can grow around the magnolia. As its already 10 years' old, I think the roots will have passed your intended cut-out. Therefore I would go for spring bulbs and perhaps only a few hellebores to make the most of the time when your magnolia is leafless.

Yoy could have a few small things like heucheras? A few different coloured ones for all year round interest and a few spring bulbs, dafts and tulips, you could even sow wildflower seed around it if you took some of the grass away?!

Also, your garden looks wonderful :)

Yes, lovely garden, but to be honest, I wouldn't underplant - magnolias dislike root disturbance intensely. I might risk digging an area to try and squeeze in a late flowering clematis though, something like Jackmanii - these need pruning back to about 8 inches during mid winter, so there'll be no dead stems cluttering up the magnolia blooms, and the jackmanii or viticella group (Prune Group 3) don't start flowering much before end of June early July. You would, though, need to loosely wrap a trunk with clematis mesh to let the clematis have something to grip onto until it got high enough in the tree each year, and you'd need to plant it further out, so a stick or something to tie it to, leaning back towards the trunk, where the mesh is, will be necessary.

Thanks for the feedback guys I was thinking of cutting the grass away in circular pattern, maybe placing some rocks around not exactly a rockery. but it would allow for more soil to be added in places allowing for deeper rooted plants to thrive without stress on the Magnolia roots ? and then some colourful and long flowering plants between them.

That sounds lovely :)

Sounds like a plan - but don't raise the soil level at the base of the tree around the trunks.

Yes Bamboo I'll be careful with the soil around the base of the tree. I'm assuming it could lead to rot? really appreciate you all taking time to help thankyou :)

Yes, foot and butt rots and other possible problems which may lead to death of the tree.

Thanks for the advice bamboo I'll make sure I watch what I'm doing as I'd hate to lose it

Do you still have the log edging around it? You could build the soil level up on the outside of it and leave it there to keep the soil around the base of the tree at its original level :)

I only a small bit of log edging left Dan I could buy more! but don't want to end up putting the log through any roots

That's a good point! My neighbours did that with theirs, they put the toll around it and fixed it loosely, planted daffodils at the tree base and then constructed a small border around their tree :)

It would be a nice way to go! I just don't want to risk damaging the tree as it's taken ten years to get it to this size would be a crime to kill it plus the Mrs would kill me lol

You have a lovely garden! Great idea to add a bit of colour around the base of the Magnolia: white and pink perennial geraniums would look good.

My magnolia is a Stellata so it may be different but the roots are so near the surface that all I have dared plant are a few small spring bulbs - anemone blanda and scillas.
If yours is the same planting anything would cut through a lot of roots. I would hesitate to plant anything but small bulbs however tempting it is. If you can't resist planting then choose very young small plants so you cause least damage. And if you do remove any grass be careful to skim it off very shallowly.
Consider containers instead? -you could vary plants with the seasons then by moving them around, and always have something to flatter the tree.

Good idea Sheila I have some pink ones I can use also some chives maybe some gypsolia and I also have some primroses for starters

I did think about containers Steragram but I just cant imagine it looking very good! I have containers ill move them about the tree this week at some point see how it looks