Like Ultra light herbalism seen here - http://web.archive.org/web/20060209234333/http://qwerts.mods.web1000.com/

Which allows you to open plants like containers, but does not dissapear if you decide not to take the ingredient? (but dissapears if you do)

The mod above is perfect, but plants dissapear even if you dont take the ingredient.

Reading http://www.mwmythicmods.com/Gluby/Gluby_Herbalism_Mods.htm, it sounds like all the others function like you're asking for.