Kurt - I'm not guru! :wink: I'm still learning too, I'm just more vocal about the tiny tidbits I have learned over the years...
IMHO, until/unless it starts crowding over the opening to the tube, I think it'd be kinda cool looking actually...
If it does start to crowd the opening, it shouldn't be too hard to get some sharp tipped scissors in there and give the Xenia a hair cut. If you're worried about it doing so, you could give it a hair cut now to trim it back away from the opening. You wouldn't have to get it all, the base would remain, and more stalks would grow from that base, but it'd just be a regular maintenance issue for you to keep it trimmed back.
If you're really worried about it, I'd get a hypodermic and inject the stalks with vinegar, but only one or two at a time so you don't get a mass die-off or get too much vinegar around the worm...