If you've done all that and stuff is still being eaten then it may not be a rabbit. It could be a deer. They can easily get over a rabbit fence. Other critters who destroy and eat stuff are groundhogs and squirrels.

Here is a link that might be useful: Deer Resistant Landscape

Join the club! Rabbits have chewed the newly planted swamp sunflowers I planted in my meadow, as they do just about anything that's not behind impenetrable bars. That's why I have my garden behind a 6' tall fence.
Rabbits even eat the sunflower seeds in broad daylight that fall to the ground beneath my bird feeder - this feeder is close to the house, so I watch them through the window. They're surprisingly big, much bigger than the cute little bunnies you see for sale at Easter time, so they can probably jump a 2' tall fence.
Sherry

I bet it's deer. Whenever I've used rabbit fencing it's kept the rabbits out.

Martha

I feel your pain Mayzu!
The absolute only way we could keep the rabbits from eating everything is with a rabbit-proof fence. And even occasionally, they get past that.
Sometimes, if you can protect the individual plants (or groups of them), with chicken wire fencing until they get older, they're not as tasty to the wabbits. It isn't attractive to have all that fencing everywhere, but you still get your flowers.
Good luck!

Rabbits dig under fencing, chew through vinyl fencing, squeeze through wire fencing with openings bigger than about 1" and jump over 2-3' high fencing. Those waskely wabbits!!

The best thing that happened in my yard is hawks. No rabbits left so far. I couldn't raise sunflowers at all. My sister calls them bobbits because they will cut down things and leave them.

LOL runmede....about the "bobbits".
I wonder if placing green leafy veggies around the plants would work??? Maybe they'd be too full to eat the butterfly plants?
When I've seen that they just cut the plants off and leave them, I wonder if they are just after the water in them?
Maybe you could also leave a plant saucer full of water in the area??? Its hard to know, though, if doing these things will just attract them more.

Rabbits get water from plants, only.Fencing really is the only way to keep them out. Plant thing rabbits love, mixed in with the stuff you dont want them to eat, you might get lucky. Only fencing works.. In AZ, rabbits each cactuses for water, not kidding. Ohhh cut up watermelon they love, lol.

Our local rabbits eat our butterfly bushes, lavender and rosemary (occasionally), honeysuckle, some sage species, wormwood (yes, it's supposed to be poisonous, but our rabbits eat through entire bushes), and more. I don't 100% trust any article that tells you what they "tend" not to eat... I've been burned over a dozen times. You have to test it in your own garden... my local rabbits have damaged or completely eaten every plant that they "tend" not to eat. We have acres of vegetation that rabbits eat so it's not like our rabbits are starving... maddening.

As the above poster wrote, although unsightly, fencing is the only method that has worked for me (liquid fence, "scarecrow", blinking lights, ultrasonic stakes, etc have all failed for me).

Chicken wire.

I had the same problem with rabbits destroying my butterfly plants. This year, only one butterfly plant came up. I up a huge tomato cage with chicken wire surrounding it.