How to survive if the flowers don't arrive.
1: Use fruit, stack seasonal fruits in glass vases: cherries and naval oranges for spring weddings, strawberries and blueberries for summer, apples for autumn, or holly and pinecones for winter.
2: Borrow flowers, good hotels will have beautiful, ornate floral arrangements in the lobby area, in public spaces and sitting areas, and in the bar/restaurant. Dressed in your wedding attire, approach the manager and explain your situation. Tip Generously.
3: Borrow from another wedding in the hotel or reception hall. Ask someone in the other wedding party if you can use flowers from that wedding. Do not be choosey - don't decline some arrangements because the colours are wrong or you don't like them. And don't approach the bride or groom, since they will likely be busy.
4: Know on neighbors doors. Explain your situation to people in nearby houses. Ask to borrow flowers from their gardens and construct bouquets and small arrangements.