I have used grass clippings with mixed results. I found that they stay to warm right around the plant (about 3" away) but is great to add to the paths between them to keep weeds down. Then I justtill it in at the end of the season. My paths are cutting paths, so I only walk on them to stake plants or cut/pinch blooms/buds off; not heavy foot traffic. I do about a 3" layer, any thinner and I found it did not get warm enough to smuggle out the weed seeds in it.

Keriann~

Oh and your dahlia poking through should be fine. Even if it does get a bit of frost damage it will be quick to repair itself.

Sorry this is late, but go to swan island a see what they have to say about grass mulch (not good), Cindy

No one likes bark mulch either? What about that compressed straw stuff?

To claify, I use the grass clippings as a walking path, not really mulch.

I have found no mulch is the best around the plants. A quick hoe-job and I am done weeding for the week. I like the look of dirt and it has been the most effective for me. Bark/mulch/clippings/straw all keep the soil too moist and promote bugs and mildew for me.

pdshop: what is your goal by using mulch? control weeds? just like the look of mulch?...??

Keriann~

Grass clippings could add organic matter to the soil, work as a light fertilizer and retain moisture. Make sure there are no seeds in it, let it wilt, apply a thin layer. Grass cuttings can start to foul/putrefy if in a thick layer or when too wet. And keep a distance from the Dahlia stems.
Then it could work. I used it often between annuals or lettuce, always keeping an eye on slugs.
Cheers, Lin

In Portland one of our all time successful growers used lawn clippings between his dahlia rows. He got grass clippings from several neighbors who had not used any weed killer on their lawns. He alternated each year and planted in the rows where the clippings were used the year before. Since grass clippings are full nitrogen, he did not use much fertilizer. He died at the age of 95 or so a couple of years ago.