Bonsaiforum
Bonsaiforum
http://www.bonsaiforum.nl/
Forumup
Offers free forum hosting using the popular phpbb message board software. forumup is a free forum host as well as a webmaster resource site.
http://bonsai.forumup.nl/?mforum=bonsai
Gardenweb
Gardenweb
http://www.uk.gardenweb.com/forums/bonsai/
Proboards28
Proboards28
http://forumskunk.proboards28.com/