Sometimes the first leaves of spring are too weak to make good printing tools. They are too young to hold their shape.
If you put them in water and work really fast, then you might be able to get a few good impressions. There are no hard and fast rules. So it is always worth a try if you are inspired by something to use in your artwork.
Maybe they could be preserved with the water and glycerin bath as described in this post.
If you want to explore monotype printing with a supportive group of people, then mark you calendar for and sign up for the next online printmaking class.
Detail here on the printmaking workshops page.