himalayan,
I have the same question as lunar. Can you explain more about '即兩者都要有根'? It is because I never planted something but bought a small pot of citrosa a couple months ago and it is getting taller and has many branches.
Many thanks.

himalayan,
Thanks for giving me the link. But I have another question now.
'分株一般指母株莖基旁長出子株, 待子株夠大, 自行長出根後 , 就可從母株剝離, 為之分株.'
How do I know '待子株夠大, 自行長出根後' since they are covered by soil?
Thanks again.