Flame color vs electrical discharge color

I don't know the right terms to frame the question but here it goes:


Neon and argon give their characteristic colors when a current is passed through them at low pressure. Balmer series etc, I understand what's going on there. 


Other compounds like boron will give a nice green in a flame test. Boron in alcohol for example. But in an electrical discharge, nothing happens.  

I'm not understanding where the difference is in the manner of exciting the boron atoms. 


How can I find a compound that will give a strong green color with an electrical discharge, at low pressure (1 torr)?


