Hi everyone can anyone please help me out to understand what's wrong with my Buxswood I planted these nearly 6 months ago. After planted they were turn bronze and before just spring they were getting green and now I have noticed they yellow leafs are dropping can any one please suggest.
Welcome to the Bunnings Workshop community @harry004. It's wonderful to have you join us, and many thanks for your questions on Buxus care.
Buxus naturally yellows coming out of Winter into Spring. However, you've suggested that they were getting green and have now reverted, which is a bit odd.
Are most of these yellowing leaves inside the bush and shadowed by the outer leaves? If so, leaves that don't receive adequate light die off as there is no point expending energy on keeping them alive if they don't produce food for the plant through photosynthesis. This is also the reason why you shouldn't let your hedges outgrow their desired shape and become lanky. When you do a hard cutback to shape, you'll find no internal leaves on the now exposed branches.
The last thing I can think of would be Buxus blight, but I'm fairly sure this isn't it. I'd give them a good feed with a nitrogen-rich fertiliser like Blood & Bone or Powerfeed, and if they don't pick up, look for other issues.
From your images, I would agree with Mitchell that, if inner leaves are yellowing (which they appear to be doing), there's nothing to worry about. A boost of fertiliser since they are expending energy growing would be beneficial.
I used powerfeed liquid fertilizer and trimmed little bit outer branches.
Will post new update if fertilizer was the issue thanks for advise.