While worn frequently in the past, boutonnières are now usually reserved for special occasions for which formal wear is standard, such as at proms, homecomings, funerals, and weddings. (Women who wear jackets on these occasions also often may wear "buttonholes", but more typically a woman would wear a corsage.) Nowadays, a lapel pin is worn more often than flowers on business suits.
Traditionally, a boutonnière was worn pushed through the lapel buttonhole (on the left, the same side as a pocket handkerchief) and the stem is held in place with a loop at the back of the lapel. The flower's calyx, if pronounced such as those of a carnation, should be fully inserted into the buttonhole which would secure it tightly and flat against the lapel. Thus the buttonhole should ideally be at least 1⅛" long for there to be enough room to fit a standard sized flower's calyx. Otherwise, the calyx would not fit into the buttonhole and the flower head would hang freely and move about in the wind.
However, on many recently made coats and jackets, the lapel is made without the loop required, which would normally sit on the reverse of the lapel, beneath the buttonhole. Sometimes, the lapel buttonhole is in the "keyhole" shape, as opposed to the traditional straight cut, or is not even pierced through, in which case the boutonnière may be pinned onto the jacket lapel, although this may be considered unsightly and continued pinning could eventually damage the cloth or silk facing.
The flower itself is often a carnation, of which the most formal is white. The classic alternative is one in clove red. Other colours and flowers may also be chosen to better coordinate with whatever else is being worn, such as a blue cornflower. A white gardenia is sometimes seen as a superior alternative to carnations given its scent and beauty.
Traditionally, certain flowers are associated with certain events, people or days:
- Red roses are worn by Englishmen on St. George's Day
- White roses are worn by residents and more widely those born and originating from the County of Yorkshire in England on Yorkshire Day the 1 August
- Blue cornflowers are often worn by Old Harrovians
- Primroses are worn for Disraeli's birthday
- Artificial poppies (mostly red) are worn for Remembrance Day
- Orchids are associated with Joseph Chamberlain
- Green carnations are sometimes associated with homosexuality