Make sure you use a glyphosate weedkiller that is not residulal that means it does not harm the soil and is inactive when in the soil. Roundup is one of those
Also you have to make a makeshift barrier to protect your plants when spraying a piece of board or similar etc

The best weedkiller is at the end of your wrist :)) Manually removing the weeds is the most thorough and least environmentally impacting method there is. Just be careful not to disrupt the soil excessively around the root zone of the tree. JM's have a quite delicate and shallow root system that resents disturbance.

It doesnt even have to be windy. The slightest drift and you could be sorry about your 'young japanese maples leaves'.
Be careful
Al

Hi Gardengal48
How are you
I also have a degree in horticulture and Landscaper
But Iam from Scotland
Your view of digging them out I agree with
But not everybody is able to do this due to disability etc
That is why i answered with weed killer because that is what the poster enquired about , No offence G
Cheers G