Spiny yellow-flowered shrub (5)
I believe the answer is:
gorse
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">spiny yellow-flowered shrub</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for gorse that I've seen before include "Moorland shrub" , "Spiny yellow-flowered shrub" , "furs, say" , "Spiny heathland shrub" , "Welsh assembly" .)