Where did this come from?

Shawn and I planted our little "porch garden" in late April. In one container, we planted a tomato plant and some carrots. The carrots never really grew, and the tomato plant seems to be frozen, for lack of a better word. We've had a number of tomatoes show up, but then they just seem to quit growing and they stay green. There's at least one tomato that's just been hanging there, not changing, for at least a month. Any ideas on this?

In the other container, we planted peas that have done pretty well. We weren't expecting them to get as tall as they have, so at this point, they're draping over the porch railing. We also forgot to have someone come water the plants when we were on our vacation, so lots of the leaves turned brown. But there are still new shoots coming out, and we've gotten a decent number of peas so far. We also planted some carrots in this container, but again, there just isn't room for them. I'm not surprised.

In this container with the peas, Shawn wanted to plant morning glories. I figured that there would be no way that everything would grow, again due to lack of room. I wasn't too surprised that the morning glories were the first to sprout in this container. The bottom picture in this post shows the morning glory sprouts. But once the peas started growing, the morning glories just stopped. We thought that was a little strange, but what do we know? We stopped thinking about them.

Until this morning. Suddenly, 3 months after we first saw sprouts, we have morning glories! These blue ones are fairly short, just growing around the bottom of the pea vines. There's also a purple one that has wrapped itself around one of the porch railing rails and is climbing its way up.
So...where did these things come from? Why on earth would they have just stopped growing for 3 months, and then randomly, out of nowhere, bloom? Seriously, we didn't even notice the vines growing. Yesterday, there were just peas in that container (with some stunted carrots), and this morning there are 3 flowers! If you have an explanation for this, feel free to share!