Which dress for a "Formal" attire wedding. Been to many black tie optional weddings but never "formal". Wedding is tomorrow in the Midwest. : r Weddingattireapproval Your dress code: Garden Party Formal. Your guests: Absolutely serving. I love a classic black tie wedding but something about garden party just speaks to me!! The Perfect Black Tie Wedding Guest Dress: 9 Gorgeous Gowns Bergdorf Goodman Wedding Guest Dresses Elegant Black Tie, Formal, and Cocktail Styles Adrianna Papell Women's Sequin Embroidery Sheath Dress Macy's What to Wear to a Black Tie Wedding: Dress Code and Outfit Ideas