Ideas for a garden wedding ceremnony?

I am getting married in the summer and we are planning a garden wedding ceremony. We have a Harpist who will play at the start of the ceremony and may play during the ceremony if we wish. It is traditional to have hymns during a ceremony, however we are a little unsure if hymns would work outside. I was wondering if you could offer any suggestions that we may be able to incorporate into our ceremony in the garden. Thank you for your time. Kind Regards.