Black flowers aren’t the easiest thing to find. There are basically 3 types of black flowers you could use and their more purple than black. Arum lilies are in season mostly in December, Dark purple tulips are only in season during spring but you could possible import them at a very high price. The third option is black roses or black morning glories, but it’s more like a dark red than a black
Instead of using black flowers you always have the option of adding black ribbons, organza and feathers.
Some more flower ideas
The wedding party