Unless you live in the Pac. Northwest it's pretty late to plant any cool-season veggies. Lettuce, carrots, and all the cabbage-y things are going to be dry and tough and bitter if planted now.
As far as ornamentals, most things can be planted as transplants now, but starting from seeds, you'd be lucky to get any bloom before the end of summer.
Please do complete your personal profile with your city/state/country. It makes things much easier to answer your questions if we know where you are. Just your hardiness zone isn't enough, as it only tells us how cold it gets on average in winter.
