One of my favorite flowers is lobelia 'Crystal Palace' for its deep intense blue. Over 20 years ago I used to plant convolvulus aka morning glories. They became VERY invasive and I've not planted any since. Whenever I see them I pull them out before they can flower. Then this year, I couldn't get it done, and this was the result:

My son spent an hour or so in October and got them out of that garden. But I'm afraid there are new seeds....

I am like you and tend to plant things by the seat of my pants, not really planned out. The New Herb garden was sort of planned, but certainly not by any color scheme or design scheme.