best way to go about modelling a rose

hello, im a blender noob and intend to mode la realistic rose, which will be rendered with cycles. How should i best go about doing so? would the best way be to model the stem and then a single rose pettle, and apply it to a curve circle? then repeat for the different layers? if im totally honest i dont know anything about roses, so i dont know exactly what to do :o
anyway, some advice is appreciated, as i really want to make a field of roses by the end of the night, and im quite stuck.

On another side note, my laptop keeps shutting down when i try to render over a 100 samples… i have an intel i3 and ubuntu 11.10, any ideas why? if i have to i will install ubtunu 12.04 alpha 2 or use windows 7 for the rendering.

CHECK YOUR REFERENCES!!!
always make sure you know what you want to model before you try to model it!
As far as the actual modelling goes, I would start with the petals, duplicate them, then add a stem, and then some thorns,
TS