There is some great advice here for you Jester.
As soon as I read your thread I new what you had to say to any prospective employer. I take it that since you have an interview then you have already passed the qualification problem. The person making the decision would not waste their time with talking with people they don't intend to possibly hire. In my field of welding an interview almost always has meant a job. I guess this is not the same with all professions but employers don't like wasting time interviewing people they don't want to hire.
Any employer or consumer will be appreciative that you are honest with the fact that you are starting to learn.
In the interview the conversation will almost definitely head towards your interest in horticulture which is Bonsai. If it doesn't make it.
Then in a manner of words you then tell them.
Bonsai is the pinnacle of horticultural achievement and that is what I strive for.
I would probably dribble on about how I would make the Bonsai area my personal project and it will be the best in the southern hemisphere, but that is why I usuualy leave any interview going why the hell couldn't I just shut up
Have fun.
With your attitude any boss would be silly not to hire you.
It's too bad your in such a hurry cause the stories I could tell you, Bushels and baskets of stories, hole crates full of stories. But if you can spare a moment I will tell you one story.