I had the regular big flowered Zinnias that I grew from seed blooming all summer. I yanked them about 2 months ago because they were done. There is a different Zinnia called Star Zinnias. They grow low to the ground(8") with small flowers(1") and come in white, yellow and orange. I always look for them and don't often find them in Spring. I found these Star Zinnias late in the season and actually cursed my friend Jen for having them at her nursery because I wanted them and it was getting too hot to plant. I bought a flat of plants and set them out on both walkways in late June. I had also ordered 2 packets of seed(really difficult to find) and none of them came up :-(
These plants are still blooming their heads off on my east facing walkway. I LOVE them! They are still annuals and will die if it gets too cold. Sometimes they reseed themselves. I hope so. You can see some of my Freesia bulbs coming up between the orange ones. Now that we're finally getting some cooler weather and overcast days, the colors really show up here.