You should save your seeds if you have Marigolds in your garden this year. Just keep the fully wilted flower heads, dry them out, and save the seeds. I'll probably show you later on this year when the Marigolds are in bloom. Right now, they're just fancy leaves :)
So here is the planter right after I put all the little propagated plants in. I put dahlias in the middle, marigolds around them, and impatiens on the outside.
Here is the planter 11 days later. Some of the impatiens have started to bloom. I have discovered that impatiens are really, really good at propagating, so you can keep the tiniest blooms on the cuttings instead of taking them all off. That way, you will have flowers sooner. These cuttings had all of their flower buds removed, but they are already flowering anyways. In the middle, the dahlia has a flower bloom ready to open.
This is the same planter 17 days later. This picture is a little closer, but you can still tell that the plants are getting bushier and that the flowers are starting to really open up. All of the impatien cuttings have flowers open now, and the dahlia has one in bloom with two more ready to go. There are actually 3 dahila cuttings in the middle, so that means one flower bud per cutting so far.
One of the lovely blog readers here asked me how soon she could expect flowers from the dahlia cuttings, so this gives you a pretty good idea of how some dahlias will have flowers ready in about 11 days, and some won't be ready until 17 days later. This is based on a finished cutting that is already about 3 weeks old and in full sun, as you'll see in a bit.
Dahlias are also really good at being propagated so you could also experiment with leaving the tiniest of flower buds on the cuttings. Don't leave any large flower buds or open flowers on your cuttings initially as this will drain too much energy from the cutting too early. Give the cutting a chance to grow strong before it focuses energy on supporting flowers.This is another planter that I started at that same time. I was experimenting with a different kind of arrangement. This one has flower varieties in clumps, and I added some other kinds of flowers like geraniums, some kind of white flower, and some of the pansy/lobelia seedlings.
11 days later, the plants are getting bigger and one of the impatiens has bloomed. This planter is on a somewhat shaded shelf and I notice that the plants are not as big as the ones in the sunny planter. Even the impatien flowers are smaller!
17 days later, there are more small-flowered impatiens in bloom and the geranium leaves are bigger. However, the dahlias are still reluctant to bloom. I think dahlias must really like full sun better. I kept one very healthy, strong dahlia in the propagating area which is bright but shaded all day, and it is also having trouble blooming. It has 2 flower buds, but they are very slow to open up. Hm...
Well, good luck with all your propagating experiments!