Will daffs survive in bermuda grass? That is pretty much all I have in my yard so I can't get away from it.
I wondered how the bulbs would do long term?
Does anyone have experience with planting bulbs in thicker invasive types of grasses?

I have found a TON of bulbs in grass, including daffs. The grass here is an amalgam of different types & I'm sure Bermuda is one of them. As long as you don't mow when the buds are popping up, that should work fine, but the show might not be what one would get from the same UNmowed bulbs.

But, would it not be more fun to have "a flower bed?" If you lay a smother now, the grass should be dead by spring. Newspaper won't cut it, but cardboard, sheet metal, plastic, or even a really thick pile of leaves would work. Use a straight shovel to sever all connections (stems/roots) around the edge of the spot, going about 4" deep should accomplish that. Then, if you use a solid border a few inches wide, like bricks or landscape timbers, you can keep the grass out reasonably easily. LMK if you want more info about starting/maintaining that!

Are you considering naturalizing them? Daffodils described as good naturalizers won't have any problem with the grass, and will persist as long as the foliage matures before mowing. I have several naturalized in thick pasture grasses, where the hay isn't cut till after the Daff leaves are dry. I've found early varieties are best, as the foliage on those ripens earlier and I don't have to wait so long to mow. If it's a short variety, like Tete a tete, you may even be able to mow on a high setting without removing much foliage.

I would to naturalize, but my dh would keep them mowed off. I have an area that about 80 ft in lenght that runs along the highway in front of my house. I planted a row of daffs, some heirloom iris and a tall orange dl. I also put in some hot pink drift roses. There is bermuda grass there and I plan on just letting things go a little natural. dh will just mow around them and some weeds in it will be ok.
I hate this bermuda, it is so invasive and the roots are deep and almost woody. It is brittle, impossible to pull out and even a little piece will grow it right back.

Anywhere with spring time sun that isn't mowed will be perfectly fine for Daffodils. I like Daffodils among daylilies, so that the dying foliage is obscured as the daylilies fill out.

Does layering cardboard and organic materials on top, kill Bermuda grass? I've found that easier than pulling or stripping out these field grasses.

nah, they just root under the ground a looooong way and come up somewhere else. I planted some shrubs last summer and they did poorly, so this summer I dug them up to move them. Well come to find out, the root balls had been taken over by bermuda. It literally choked them out. So then I am resorting to Round up around the bushes now until they get much larger and established.

Cardboard will smother grass if done correctly. You have to sever the connections of stems and roots along the edge with a shovel. I've done it many times. The grasses here are Bermuda, Bahia, wiregrass, all the tough ones. Agreed, it's WAY easier than trying to dig up grass, and you don't lose the topsoil.

I have to dig it up. It roots deeply and even if you leave a small piece of root with no top on it, it will regrow. It has like bracts along it that each will root down and grow. Besides that the grass has been here for years and the seeds would just re-sprout and take over even if the other was smothered. Why on earth anyone would plant this stuff on purpose is beyond me. I do know it is an illegal invasive in some states. I suppose the weather and soil types make a big difference in its performance.

If Hollywood knew the growth habits of Bermuda Grass it would be a star in their next blockbuster Horror film.

You can't solarize Bermuda grass. I've tried. The rhizomes go down too deep to be affected by the heat. I've also tried smothering it with leaves but once the leaves decay, the Bermuda is still there. As Bonnie references, it is the grass that ate Los Angeles.

well it is eating my MO lawn also!