I know there is a silica powder used to preserve flowers.
1. Does it work well for leaves>
2. How can I dry them on the stems? I don't like to have just the heads & then have to wire them & use floral tape to create a fake branch.
I feel the same way you do about the wires for stems. What I do is just put the flower blossoms in the silica and let the stems and leaves stick out. Not perfect but better than fighting the wires.
Don't the flowers in silica gel need to be in a sealed container or no? How long does something like that work?
I think some books on drying flowers are way too gloomy about getting good, strong stems when air-drying. With "classic" everlastings such as helichrysums and gomphrenas, the stem takes much longer to dry than the flower (which is basically dried when it's picked), but we've never found it necessary to resort to artificial stems.