You peel it off the rock, cut it, prune it back, then mount it on rubble. It's a hardy coral, many hobbyists just trim it like a macro. Actually, nerdy fun fact of the day, it exports more nutrients than your average macro.
It has been one of those corals my mom absolutely adores but I avoid like the Plague. Not my picture, but you get the idea.
My weed of choice are green star polyps...
Now, Xenia may be actually the better weed choice. Gsp grows at a slower rate, but is more aggressive and may win battles with lps by smothering. They also absorb magnesium from the water column.
Another fun fact for the day, some Palythoas will eat Xenia.
Staring at some of my palys, I wouldn't doubt it.
Finally, check your nitrates, Xenia, being a nitrate exporter, will thrive where there are nitrates. Remove the nitrates, and you may possibly control the Xenia.
Hope this was helpful?
L