The background is optional, your drawing will look good anyway. This dark background is really easy to make. Don't start drawing it with your pencil, that takes too much time and it's a real pain because your hand will hurt. Instead, get a small knife, or any blade, and start scraping graphite powder all around the rose(please be careful so you don't cut yourself). I have graphite sticks, which are as thick as normal pencils, but with no wood, only mine . You'll need A LOT of graphite powder, so if you only have normal pencils, it's gonna take some time to get enough of it. After you have graphite powder all around the rose, get a bit of cotton and start smudging until the paper turns black. If it doesn't, put more powder on that area. Be careful near the petals, you don't want powder on them, and if by accident you do manage to get powder on them, slowly erase. I think you're pretty much done.