It's been a long time since I made Buttercream roses and I can't figure out what I'm doing wrong! 

I leave my buttercream in the fridge until I'm ready to start piping so it's not too soft. But the petals keep drooping and have a jagged look to them. I set them in the fridge to harden but when I'm ready to take them out the petals have all formed together so there's no longer any definition. What am I doing wrong?

Oh, i wish I could help. Buttercream roses are not my friend either. I know it takes patience and practice, practice, practice. 

Sounds like your icing is too soft. Don't put it in the fridge, because it's probably softening up as it warms up, and the heat from your hands won't help. Make sure it's the right consistency at room temp, so add more sugar or less liquid the next time that you make it. If it's too soft it's to soft, it won't matter if you put it in the fridge or not.

Agh, TOO soft, not to soft. I can't stand it.

you can add cornstarch too -- i always kept a skaker of cornstarch and a squirt bottle of water at my station to firm up or loosen my icing at a moment's notice

Definitely, your icing is too soft. You probably have too much liquid in. When I add milk or cream I only put a tablespoon at a time. Some people don't add any liquid. 

Adding cornstarch or 10X sugar as the others have said should help.

Good luck and let us know if adding the above helps you.

I agree w/all the others, your icing is too soft to begin with.  If you post your recipe we can help better.   Are you adding liquid to the icing?  For piping flowers there should not be any.  

You mention the flowers having ragged edges.  You might not have a totally clean tip.  Take a toothpick or pin the run it around especially at the narrowest end.  If it is clean, then the icing needs to be creamier by adding a bit more fat.  BUT.........I must say, I LOVE roses with cracked edges :)

The recipe I use is 1/2 lb butter, 2 cups shortening, 2 tbsp meringue powder, 1 tsp vanilla, 1 tsp butter flavoring, 1/4 tsp salt, and 2 lbs 10x sugar. I tried adding more 10x sugar, opening the end of my tip a little more, and nothing helped. I don't add any liquid other than the flavoring. Aaggh this is frustrating!

i think three cups of fat to 2#s of sugar is way too much fat -- i use one cup of fat to 2#s of powd sugar -- some people use two cups of fat to 2#s of sugar -- but three cups is too much unless you add a 1/2 cup or more of cornstarch

or another pound of sugar

I agree with K8memphis, too much fat. The ratio for a regular buttercream is 1 cup of fat to 4 cups (1 lb) of sugar.

I agree w/the others that is much too much fat.  For icing flowers you should be usi8ng only 1 C shortening w/the 1/2 C butter for 2# powdered sguar.   I don't like adding cornstarch = I can taste it every time.  It is much better to cut down on the fat in your recipe.  Try that and I bet you will see a huge improvement in your roses :)

Thanks everyone. I'll try making it with less fat and see what happens.