From pot to ground - yellowing leaves

We had a Argyrocytisus battandieri 'Yellow Tail' sitting happily in a pot, whilst I sorted out our new garden; I finally got around to putting it in the ground a week and a half ago.

It has since developed yellow leaves, which fall to the group when brushed.  The weather hasn't been particularly wet or dry, so is this simply shock?  Due to the size of the pot, much of the pot soil started to break apart during the transfer, so the roots will have been reasonably disturbed.

Thanks in advance,
Russell.