Spiny shrub (5)
I believe the answer is:
gorse
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">spiny shrub</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for gorse that I've seen before include "Spiny yellow-flowered shrub" , "Spiny heathland shrub" , "Wild shrub with yellow flowers and sharp thorns, common on hillsides" , "Prickly shrub with yellow flowers" , "Prickly heath shrub" .)