By Hummingbird
United Kingdom 
Hi i have a 6 foot healthy Acer palmatum that i have grown from a baby, it is in a large half barrel container, every year it has been a canopy of red but this year the leaves are a bit sparse,some of the younger growth hasnt leafed but still seem healthy and just today some of the lower leafs fell off. getting worried as to what the problem is, could it be the severe frost that has stunted the growth and causing problems? would appreciate any help and advice. many thanks Sandy.
30 May, 2010
Answers
Six feet is pretty big for a half barrel. For right now, I would prune it back lightly and feed it an acid-forming food. That just to keep it healthy till it's a better time to repot it in a larger container--or plant it in the garden. Bonsai techniques, to limit its growth, may allow you to keep it in the same or a similar half barrel, if space is tight.
31 May, 2010
thankyou Pip c and Tuqbrethil for your advice, have taken it onboard, just to let you know i feed my acer every 2 to 3 wks during the growing season with sequested iron hope thats been the right thing to do! many thanks Sandy.
31 May, 2010
Giving it iron without the other nutrients is like giving your dog vitamin tablets, but without any kibble. I would use fish emulsion, or Miracle-Gro for Acid-Loving Plants, or a timed release, like Osmocote.
31 May, 2010
Many thanks i will start feeding with miracle-grow as well as iron ,thanks again Sandy.
3 Jun, 2010
It sounds as though it might be potbound; six foot trees may not take to kindly to being in pots. I don't think it would be frost because Acers are generally hardy. Perhaps you would find advice on the Acer genus page.
31 May, 2010