Tree of coastal swamps (8)
I believe the answer is:
mangrove
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tree of coastal swamps</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for mangrove that I've seen before include "one that's swamped?" , "Swamp tree" , "Coastal swamp plant" , "Tree growing on tropical coasts and in muddy swamps" , "whose roots may be waterlogged" .)