"Q. What kind of 花 is that on the cover, and what does it mean?
A. That is a ruffled tulip. As for the meaning... If you've read the Twilight FAQ, あなた know that the 林檎, アップル cover had a lot of meaning for me, and I was an active part of the covering process. However, that experience is もっと見る the exception than the rule in the publishing world. Something to keep in mind if あなた intend to embark on a career as a writer: lots of things あなた might expect to be under your control are not. Covers, for example. Those are mostly up to the publisher and the marketing and sales departments. So I don't know what the チューリップ means—I didn't have anything to do with this one."
あなた can find it under Twilight Series > New Moon > FAQ. Hope I helped :P
Lot's of people have different opinions on this, but I believe that the 花 represents Bella's heart. Why? Because I think that it's red because she's hurt inside, and the white represents a little bit of hope/love that's still there. However there's a petal dropping off because she feels as if she's falling apart. But, that's just my view, most people's are different.
There are sites that say the 花 has absolutely no meaning seeing as Stephanie Meyer did not choose the cover for New Moon. Then there are some sites that say the ruffled チューリップ represents a beautiful バタフライ, 蝶 coming into view. I'm not sure which one is true, but that's all I could find. (:
I believe that the this 花 fades, and it represents as she feels Bella when Edward goes away, but for it me represents sinceBella's ハート, 心 is in this book, the white thing represents the cold (is Edward) and the red thing is the heat in this case he would be Jacob.
To Stephenie Meyer, the 花 doesn't have any meaning. But I personally think the tied in red and white shows Jacob coming into her life. The answer is basically up to you.