What do I do with my lemon eucalyptus?

What do I do with my lemon eucalyptus?

Hi guys, I have a tiny bit of a problem regarding how I should deal with my lemon eucalyptus. I live in a flat/apartment. That means a severe lack of space. My lemon eucalyptus has grown so tall on the ledge I placed it at that I don't know what to do with it now. Its tips are touching the ceiling; problem is I have absolutely no more space to shift it around with. Should I prune it? Will pruning stunt the growth after that? Someone suggests that I should bonsai it. But I'm not sure if it'd take to bonsai-ing after almost a year of unchecked growth. For reference, two pictures:
some people say garden art is tacky

some people say garden art is tacky

Bathroom Makeover :)

Bathroom Makeover :)

Yay finally!

Yay finally!

Untouched Canvas

Untouched Canvas

The rain.

The rain.

Preen : should I use it?

Preen : should I use it?