Serpent said: Marigolds and chrysanthemums, sea holly, datura, allium. They don't smell nice, so most creatures are not even tempted.
gardenfish said: I've planted the datura in too small pots for two years in a row, they really need a large pot, so maybe not? It is a big, gangly plant.
Murky said: Just curious why you don't think marigolds would fit where you want? They come in such a huge variety of shapes and heights now, from 6" up to 4', single small flowers to huge pompom types, you should be able to find something to fit your planters. I've grown them in pots several years and they did beautifully, blooming from late spring until late fall. In fact, when I had some big pompom types, they were one of the longest lasting flowers that kept going when others had started dying back from the cold weather in fall. Growing them in a pot often keeps them shorter for me, even the pompom types never got over 12".
Edit just to add that the reason I had the big pompoms is because they're usually not scented, I'm not a fan of the marigold scent. My mother used to make me help her plant seeds every year and I hated the smell, it would seem to stay on my skin for days after planting. Just in case you like or dislike scented marigolds.
Murky said: Maybe a workaround would be to buy just a handful of already started marigolds locally that are blooming, and the seeds coming up around them will fill the planters in more a bit later? I know I enjoy seeing my planters slowly fill up during the summer as the plants get older rather than an instantly filled container. My containers look downright pathetic when first planted in fact!