I always collect my jam jars as they look so cute and can be used for so many things (including homemade jam of course)!
However my new favourite use of my jars is to hold fresh flowers. I find that flowers with a strong stem that can be cut short work really well. (A tulip's weak stem would require a taller holder to support the weaker stem for example.) Also flowers that have a wide head or have small clusters of flowers look best.
The end result is a feminine rustic look that I just love!