If you are getting married in June I do not recommend you put real flowers in your hair. By the end of the evening they will look very sad. Tiny roses seem to hold up, as long as they are not white or cream since they will go brown. Peonies are very popular but if it’s hot and they are exposed to a lot of sun they will droop. I promise. If you absolutely insist on real flowers keep them hydrated in the fridge till the very last minute. If you want orchids in your hair, I would highly recommend you look for a good quality fake variety. I know you have seen the fashion shoots with fresh flowers in their hair but those flowers only had to look good for an hour maximum. Another option is to have replacements at hand but it also means you need a hairdresser or reliable friend.