The ZIP is the first answer.
1-800-Flowers can show a bouquet that looks available and still have no route to the address on your day. The ZIP code is what the calendar is actually checking. A downtown address and a house twenty miles out can sit in the same city name and get two different dates.
Put in the recipient ZIP, not yours, unless the flowers are coming to you. Then look at the first date the page will accept. If that date is later than the occasion, the photograph does not matter yet.
Tuesday, Saturday, and a service are not the same slot.
A weekday birthday is the ordinary case. Saturday delivery is thinner, and a Sunday or a holiday can move to the next business day without the picture changing. Sympathy and funeral work often has a morning window that a birthday order does not. If the flowers have to be in the room before a service, say the hour, not just the date.
Someone has to be there, or the building has to accept a delivery without them. A door code, a front desk, and a “leave it” note are part of the date. A perfect ZIP with nobody home is a bouquet in a hallway.
Same-day is a morning decision.
Same-day, where it exists, usually cuts off before noon and favors dense metro ZIPs. If you are asking in the afternoon, read the next date instead of refreshing the same bouquet. Rural routes and many small cities simply do not offer it. That is a calendar fact, not a sold-out flower.
A product photo is also not a promise that those exact stems leave a shop that afternoon. Local florists substitute for what is fresh. If a color family matters more than a species, say the color. If the species is the gift, check that the date still offers it.
When the date holds, talk about height.
For a dinner, ask for a centerpiece low enough that guests see each other. Hydrangea in a wide bowl does that. A tall hand-tied bunch is for a vase by the door or a kitchen counter, not for the middle of a conversation.
Bring three words: the date that survived the ZIP, the color, and the place it will sit. The arrangement notes and the bouquet journal are the rest of the sentence.