If you need to form a pattern in frosting, quickly and easily:
Might I suggest what I refer to as "the family pattern" (as in, a pattern that seems to be in my family):

My 49th birthday cake, on Flickr (tm)

Simply plow a series of furrows in the cake, with a small, round-end, frosting spatula, then make crosswise cuts in alternating directions in the furrows.

If I don't have time for that, I probably don't have time to do much more than make the cake look like a rustic stucco job.

Thanks guys, no worries about the "ombre" name .. I'll try it next time with a spoon and see if I get better control with that .. I just saw your multi colored petal cake tonight .. it's gorgeous!  Maybe one day ..
 

AGood luck, if you are speaking about my rainbow petal cake, thank you so much.

Ummm...Maybe you have HOT hands...I know I do. Its my problem when icing anything. When I'm nervous my hands get hot. That in turns heats up the icing and makes the consistency change. Try taking a break and sticking the piping bag back in the fridge or run your hands under some cold water before you begin.

Ok so yes my secret is out..
 

Yep, that was the one I was talking about!  hahaha, yes, I do also suffer from hot hands!  But my hands are always hot and my icing consistency usually works for me .. but I'll try sticking the frosting in the fridge while working on this technique ..
 

can i make a technique suggestion? since the "petals" will be dragged to one side anyway, why not try to do a smooth shell for each "blob/petal" and then pull from there, so that the blob is already pointing in the direction that you want it to go, and you won't have to do a straight ball on with your tip on top, making it difficult to see what you're doing.

I also count when I'm making a large shape like that, so that I have some gauge of how much BC is coming out of the bag. 

jen

AI've seen this style before but never really paid any real attention to it....now I'm gonna have to at least try this out to see how it looks..to the O.P. don't give up! You got this. ;-)

AI agree with tesso, try a spoon! I tried this a couple of months ago, very slow at first, but by the time I covered half the cake I was able to speed things up. I used a baby spoon, dipped in water and slightly wiped dry after each "swipe". I also suggest you work at eye level to ensure you are dragging the icing straight.