That's because they weren't exposed to the weather as much. Essentially these were 'shrinkwrapped' in nature's own version of Cosmoline. No bacteria, no free oxygen. Once did this with a rose to see how long it would last and it basically was perfect until we moved house. Many years and not even the slightest change, it didn't even lose color.
That would actually be a brilliant treatment to give wedding bouquets! I’ve never heard of Cosmoline. Going to look it up. Thanks!