They can, it doesn't matter what other people tell you, they can be used for what ever you believe they can be used for. Say, they make you happy, YOU can use that as something for a happy spell. Or, the most common I know of is just preservation to put into your book of shadows
Pressed flowers can certainly be used in magic :) They are often used in making candles and for stuffing inside poppets, etc. As for the symbolism of the flowers - it would depend on the flower used and how it is being used. Any book on herbs and plants in magic can be used as a guide. I really like Scott Cunningham's guide on Brews, Incenses and .... oh... I can't remember the title. But it's often available in bookstores :)
Re: Pressed flowers
By: Misanthropy Moderator / Knowledgeable Oct 28, 2016
Post # 6
I use them when making herbal sachets and elixirs. They can be found fairly easily at craft stores (if you're unable to make your own). They work quick if you're in a pinch and don't have the fresh or other dried forms of the flowers or herbs that you need on hand at the time.
I like to charge mine and say a small chant over them associated with my intent before I incorporate them into spells, sachets, etc.