What does 招花 mean to anyone? I read it in a book.

It is supposed to be a way children sometimes play.

You'd get substantially better responses if you explained where you got 招花 from (which book?), and in which context the word appears (i.e., give the whole sentence).  Chinese changes across time and location.

The usual phrases are 玩花招 (wán huāzhāo) and 耍花招 (shuǎ huāzhāo) meaning "to play tricks" wherein 花招 are the "tricks".  If I were to guess (without additional context) then 招花 is probably just 花招.  But it could be something completely different, like some kind of play on words.

Chances are, if it's a game for kids, '招花' is just a mix-up or a fun name for '传花'(chuán huā, lit. 'pass flower'). It's basically the Chinese version of 'hot potato' -you know, '击鼓传花'(jī gǔ chuán huā, lit. 'beat drum pass flower', where you pass something around and don't want to be the one caught with it when the music stops.