Note: Finding the origins for phrases can be very difficult a lot of the time, as it's near impossible the majority of the time to find that one person or even area where an idiom started. For the most part, what's given are possibilities in how a phrase could have originated, but not necessarily how it actually did. Additionally, early recorded forms of a saying will be given, and these tend to come from old books, newspapers, poems, or plays.
However, if phrases are being printed in forms of media, like a newspaper, that usually means it's already a well known saying and is probably much older.Ultimately, you get an approximate on how long a phrase has been used for, and gain a little understanding on where a phrase's roots are from.
knowyourphrase.com - Sayings and Phrases - Meanings and Origins
Typically used to describe someone who is avoiding the main point in a conversation;
failing to get to the bottom line.
When someone is taking too long to get to the core of what they're trying say, people
This phrase is believed to have come from hunting. According to Idiomation, back in medieval times, hunters would hire men who would assist them in the hunt by flushing out animals from within the brush. This could be done by whacking the bushes with a stick, perhaps even accompaning the whacking with some loud shouting; the point was to make a bunch of noise in order to scare birds and other animals out from the cover of the bushes, making them easier targets for the hunter.
Hitting the bushes directly probably wasn't always the best approach to take. While harmless animals, like birds, rabbits, or squirrels, might emerge from the brush, the more dangerous animals should also be considered for safety reasons. You never know, for instance, if a wild boar is going to charge out after being startled and cause injuries with its sharp tusks. Hence, at times, perhaps these 'beaters' of the brush, when trying to be on the cautious side, would literally beat around the bush instead of hitting them directly. This would be comparable to how people, at times, do not directly get to the point of what they are saying, but instead talk around it. So perhaps that last part about the beaters hitting around the bushes is where the phrase derives its figurative meaning, or perhaps not. In any case, this expression is still believed to have its roots somewhere in hunting, along the lines of what has been mentioned above.
To go along with what's already been said, the earliest known recording of the phrase with 'about' in it is found written in a poem from the 16th century. The poem, written by George Gascoigne, 1572, mentions the beating of bushes with birds being caught as a result:
"To thinke bowe he abused was, alas my heart it bleedes:
He bet about the bushe, whiles other caught the birds …"