Hi,can anyone please recommend a suitable weed killer that’s safe to use on weeds in the pots of my dads beautiful trees? I only have a handful to up keep he has 50 so it’s a full time job for him caring for them all ... would be grateful for any advice given .. many thanks in advance x

All weed killers kill plants.. So I would never use them in pots.
In the end it is a matter of keeping to it and removing green as you see it.

Thank you for the good advise,have spoken to my dad & advised no weed killer .... also having a problem I have noticed myself with 1 of my trees any idea what’s caused or causing this problem,all other trees are perfectly healthy so I am baffled .. we had a really harsh winter artic winds freezing temperatures & late snow falls all not normal winter weather for us in the uk .. any advice would be really appreciated as I fear I may lose this little tree x