Above: Siberian elm samara in New York City. Like other fruit, nut, and winged seed trees (like maples), elms can have mast years, or a bumper crop, where branches appear to be bursting with ...

Siberian elm (Ulmus pumila) is a fast-growing, aggressive tree that tolerates all kinds of difficult growing conditions. But it’s messy, seeds itself all over the place and frankly isn’t the ...