hey mandude.
I'm also a first-time grower. And I might be wrong from a lot of different perspectives but what's the worst that could happen?
If you were to plant in Mid-june, there is no way ther would be frost danger unless you live in chile, alaska or any other place. You live in the midwest. You should be good to go for that.
However, you ask that you plant in June and harvest by August. AFAIK, unless you get an "early" strain, you won't be able to harvest until late sept.
There is always a possibility or choice of you growing it indoors for a short while then transferring it outside. This would get the plant a higher chance of surviving.
And I don't know much about conifers so I'll leave the last question alone
hope this helps.