"hos" would be liable to mislead the reader, whereas "ho's" is clearer. But the normal way to avoid that would be to spell the plural "hoes". That makes for a potential ambiguity, but the context would reduce the likelihood of anyone thinking the word referred to garden implements.

Better still, avoid the word entirely.

If "ho" seen as an abbreviation for "whore" I think that since the "w" is silent anyway it's possible to justify not giving it an apostrophe, and a single apostrophe is sufficient to cover any number of omitted letters.

But maybe the silent "w" is there in any case, and it really ought to be written - if it must be written - as "who' ", plural "who's"...