I made my cardbox...pics attached, and bridesmaid dress too

I spent 4 nights making my cardbox because I couldn't find one I liked. I also attached a picture of my bridesmaid dresses and the color flowers we are using. My invitations have filigree on them and are black white and pink


Here is where need some advice:

I am doing centerpieces with flowers in tall tube vases, submerged in water and votive candles floating on top. There will be three on each table. I wanted some element of black in the centerpieces, but don't want them to be morbid. The flowers inside each tube will be hot pink, but where can I but black, or maybe incorporate the filigree?

Help!

Sorry the pic quality is poor...it's from my cell phone.