Magnolia Susan not thriving

Hello
We have a magnolia in a large pot in the sun. It has flowered although poorly in the past but is failing to do so now. It's not really thriving.
Should we report (If so is no advised?). Or weed and mulch? Or add nutrients? Or talk to it?
All advice most gratefully received.

 

Yes. Last one is only for your benefit though

Any idea what sort of magnolia? Some want an acid soil and if so it would be important to get that right

 

Magnolia Susan is the variety and her name. I meant 'repot' not 'report' btw...the police have enough on their hands...

Repot with ericaceous compost?

 

@Sarah Eley
I grow magnolia Susan and it is currently flowering well. It is a shallow rooted plant, so it might be better in a wider rather than deeper pot. I mulch mine with garden compost every year so that might help. Watering is also important as flower buds may fail to form or abort if the plant gets too dry especially over the summer. This is something you need to watch as yours in a pot in the sun. Mine gets sun for the morning and then is in shade for the rest of the time so the roots don't get too hot.

 

I see it in the Title now Doh!

RHS says "Acid / Neutral" so if you have the option I think Ericaeous compost would be best (and an Acid feed too ... and rainwater not hard-water from mains (although "any water is better than none" if you run out of Rainwater in the Summer)

I use these 100's and 1,000's for my Acid Lovers which last 3 months

 

Thank you everyone for kind advice. We removed Susan from her pot to find she is rather pot bound and there was an ants' nest in the bottom. We soaked the root ball, teased it out, planted with ericaceous compost and within a couple of days new shoots have appeared. Happy!

 

Just thought you might like to see the impact repotting has had on our Susan!