Please help this clueless furner with homecoming etiquette

[Anonymous]

DD is going to the homecoming dance with her BF on Saturday.
Should I get him a boutonniere? I've never been to a high school dance so I don't know how formal or informal homecoming is.
If I should get a boutonniere, do I just show up at the florist's and they'll have some? Or do I need to call tomorrow and get them to make one for Saturday? (I assume I have to pick it up that day so the flowers don't die). What do I say if they ask me what kind I want? I don't know anything beyond the word boutonniere.

[Anonymous]

Yes to the boutonniere. You can get them at a florist but you can often get them at Giant. Best to call ahead to a florist. All you want is a plain white one.

[Anonymous]

Not for homecoming. Yes for prom.

[Anonymous]

Ask a parent of an older kid. Different schools have different traditions. Ours does flowers for all dances if you have a date. I usually call a day or two in advance for a boutonnière.

[Anonymous]

My boys (really me) bought the girl's flowers and the boutonniere. This was because they wanted them to match.