Hi Manx,
You don't say what the problem with your maples is. Just how are they ailing? Leaves turning brown, leaves dropping off, bugs eating them, etc. Were they planted 15 months ago or 1 1/2 months ago? Were they rootbound when they were planted?
I don't know where Brighton is. What state or hardiness
zone are you in?
They prefer part shade to shade and can get burned in the sun. I wouldn't use miracid. Stressed
plants are best not fertilized, especially with a synthetic fertilizer. If you do fertilize, use either compost tea or compost as a mulch.
If you get back to us with more info we can try and help you.
Newt