Dandelions are the starting flower. You do want to buy some and plant them. You then will be able to dig them up once they grow (which auto-sells them) using the shovel.
Sorry if that description confused you. It was just meant to be a bit cheeky.
Ahhh, thank you! Yeah I couldn't figure out why there would be a weed for sale, any my rent is like 2100 so I didn't think I could waste any money buying something I couldn't sell. :)
I was in the same boat as you until after a day realizing no money was coming my way. I figured let's just buy one - plant it - see what happens. Much to my surprise when I turned a profit I felt a little silly having not tried it sooner.
totally did the same thing, took me a day and a half to work it out