We've been living in the same house for decades, and I've always had a garden. In the beginning, I would plant some seeds in one small area behind the house, hope for the best, pull a few weeds, and that would be my contribution to the garden. I don't remember all the flowers in my original garden other than California poppies, salvia and (possibly) some alyssum? Not sure. I do know that I planted them from seed.
As the years went on, I made more space for flowers. And more. And more. For a house that has large lilac hedges running down both sides of the back yard, shorter spirea hedges running down both sides of the front, a magnolia tree, a silver maple tree, and a lot of grass on a modest lot, it's amazing how many places I found to put plants. At the moment I have six areas, plus flower pots in other places.
I've discovered that I need to keep track of what works and what doesn't, and also, I'm just a little fussy that way. So every year, I keep records of what I bought, I take a lot of photos (not great photos), and at the end of the season, I create a Word file where I talk about what worked and what didn't. Sometimes there are photos, so that I'll be able to match the names to the flower. I might include when I started the seeds inside if I planted from seed and when I set them outside. I'll note when I bought bedding plants and how many of each. For the dahlias, I'll include dates or approximate dates of when they bloomed and how prolific the blooms were (maybe the size of the blooms). That's important because some of them bloom very late, so you might spend most of the season with just a plant and no flowers until fall. That might play into whether I replant that particular variety the next year.
If there are self-seeding plants (larkspur, sometimes wild sunflowers), I'll make note of how well they self-seeded. All of that goes into a file (or several files) and gets put into a folder on my computer. Then when I'm planning my garden next year, I'll have of what worked, what didn't, and how I want to proceed the next year. It's not particularly concise. I know when things flowered, because I took photos, but I may only know that I planted seeds indoors in March, not the correct date (because I'm so excited about planting that I forget to note the dates).
In the long run, this kind of note-taking pays off. After this year, I know that if I plant in the bed immediately behind the house, I should avoid cosmos because insects ate them this year (while the plants survived in other beds). I might also have to put down some sort of slug preventative in that bed, because they chewed up some dahlias pretty badly. On the other hand, New Guinea impatiens (from bedding plants), Sunpatiens (also from bedding plants) and two types of clematis did quite well in that same bed.
It's all part of the fun of gardening, trying new things every year and seeing what works.
Myrna