@delta575 You can certainly draw a ternary plot with Bokeh, no question, but there is nothing currently built in to Bokeh that would help with this directly. You would need to draw any axes labels, grid lines, etc. manually yourself, and you would need to convert from ternary coordinates to some arbitrary cartesian frame as well.
I would not be opposed to thinking about ways to make ternary plots more accessible, but it will require new development and would be most likely to happen with a motivated collaborator. In any case, a GithHub issue would be the place to discuss a feature request.