based from my experience

morning glory/moonflower - soak 24 hours, direct sow 2 weeks before last frost. I'll grow them indoor next year

nasturtium - direct sow 3 weeks before last frost

cleome - i direct sow them late April but even direct sowing mid May still works

Poppy - I spread them in October. There is another annual that I also spread in October. I couldn't remember and my brain is aching now :( They're black seeds, blue flowering.

Poppies are best if you just scatter your seeds in late fall/winter, even over the snow.
Nasturtiums are some of my favorites - very easy to grow, and so pretty in window boxes and containers.

Linnea,

They are not on your list, but zinnias are one of my favorites for direct sowing. I wait until after a "safe" no-frost date (somewhere between May 1 and May 15 here). After sowing them about 1/4-inch deep, I sprinkle the seedbed to wet it down without washing anything away, and they are usually up in a little less than a week.

ZM

v1rtu0s1ty was it Nigella?

Thanks! And zinnias sound great too!

Are any of these especially prone to being bunny food as seedlings?

flora_uk, I remember it now. It's larkspur. :)

Linnea,

"Are any of these especially prone to being bunny food as seedlings?"

I have had cutworms kill some zinnia seedlings. If you have a lot of rabbits, they might do some damage to your zinnias. This listing of Rabbit Resistant Plants notes that zinnias are "more likely to be nibbled, especially new foliage and first buds." In my opinion, zinnias are moderately susceptible to rabbit damage, although I have been lucky and haven't experienced any noticeable rabbit damage. But we live in a rural area and the rabbits around here have an abundance of wild alternatives to our garden plants.

On your list, I think that rabbits don't damage Cleome (Spider Flower). I have grown morning glories, vining nasturtiums, and moonflowers without rabbit damage, but that could be that the rabbits had other things available that they liked better. I am personally more concerned about cutworms than either rabbits or deer.

ZM

Larkspur! Oooh!

I think I had trouble with morning glories before, as far as rabbit damage. The last time I got some seedlings in a swap, I ended up having to make little fences around them.

About cleome, if you don't want a carpet of plants next year, keep trimming off the seed pods before they ripen & split. I miss this plant & can't find seeds anywhere around here. Go figure!

Nobody mentioned the easiest of all - sunflowers!

I want these more as fillers in and around my perennials, so sunflowers would be too big/thick or leafy as a filler plant.

I bought Cleome one year and intentionally let it go to seed, as I read here that worked for peaople. I had a number of seedlings the next spring, but only a few plants that grew enough to flower. The next year, nothing! :(

If poppies are better off being sown in late winter, have I missed the boat on those?

I can testify to the ease of zinnias. Last year I just scratched up the good soil in one of my perennial beds with a hand cultivator, sprinkled the seeds over the area liberally, and firmly pressed them into the soil. By keeping the soil moist, they came right up...but, the slugs got the first batch. So, the second time around, I sowed slug bait with the seeds and had no problem. Although I have had rabbits from time to time, they have never bothered zinnias...could be just luck...

Marigolds are easy to direct sow, as are Jewels of Opar (I like the chartreuse foliage), and everything else on your list. To get cleome going, I have had good luck with sowing it in pots and refrigerating them for two weeks. This seems to speed germination.

Six weeks or so ago I sprinkled some three-year-old Shirley Poppy seeds in a bed I've been having problems trying to get anything to grow but the daffodils that are in there. I plant only annuals in this bed to grow when the daffodils are finished. About three weeks ago I saw poppy sprouts all over in the bed, which surprised me really because I thought the seeds would be too old. So then I sprinkled quite heavily Tidy Tips (Layia platyglossa), Farewell-To-Spring (Clarkia amoena) and Queen Anne's Thimbles (Gilia capitata). I now have lots of little sprouts in that bed, and if it would ever get warm and the sun shine, those little babies would grow faster. All I did was sprinkle them around just before a rain so the rain would beat the seeds into the soil to give the seeds better contact with the soil and not get blown away. I hope the plants do well, otherwise next year I'll be on the hunt for something else to try to grow in this bed.

Karen

tepulus- I would like to know how the Gilia capitata did for you. I started some under lights and will transplant the out soon, but this fall I plan to direct sow some, since they seem to be one of those west coast wet/dry season adapted annuals that grow all winter then bloom in late spring/early summer when it's still moist. Limnanthes douglasii is similar and I grew it the last 2 years. The second year I was surprised to see it come up thickly with the fall rains then make it through the winter, so I expect it to bloom earlier this spring and put on more of a show. Some annual poppies may also do this well. Most of the annuals mentioned in the first post have not done well for me, except nasturtiums, and they have not done well with self-sowing.

Calendula
Viola (heartsease/johnny-jump-up)
Borage

I've had the same issue with nasturtiums, but they do better if you help them by burying the seeds for them in fall.

For the bunnies, try pepper pellets. Worked on my groundhog

v1rtu0s1ty, you might want to try Winter Sowing your annuals to ensure germination.

"Nobody mentioned the easiest of all - sunflowers!"

Not on my property. I've tried everything. They grow to about four feet and flop. Good sun too.

Cleomes easiest followed by Zinnia and marigolds. I even had a bugger of a time getting morning glory going a few years back. Now they're all over, but not the color I really wanted:(

Moonflowers do great in some locations where I am. Clay soil seems to be a favorite. Never have been able to get seeds from previous year to germinate...don't know why. Is there a best time to collect them?

nemophila, limnanthes, godetia, escholtzia, legousia. gypsophila, convolvulous, cornflower, agrostemma, cosmos, phlox, orlaya, ammi, layia, ursinia, collinia, zinnia, lavatera, phacelia, linaria,chrysanthemum segetum, calendula.......some of the easy annuals I have sown over the last few years.