What's That Weed?

What’s That Weed?

Siberian Elm (Ulmus pumila)

by Pam Wolfe

If you google “Siberian elm,” you’ll find everything from invective to a recipe for a salad featuring the (oh so many) fresh seeds. A native of China, Siberia, Manchuria, and Korea, this plant is listed as a Class C noxious weed by the New Mexico Department of Agriculture. Siberian elm exhibits all the characteristics of so many species that are now designated as invasive in North America: it’s opportunistic on disturbed ground, it’s a prodigious seed producer, and it was introduced intentionally to address specific environmental problems (extreme conditions, Dutch elm disease). This tough tree comprises 13.5 percent of the canopy in the 16 Santa Fe city parks thus far studied by the Santa Fe Public Spaces Tree Inventory.

Santa Fe city code (14-8.4) prohibits the planting of the tree—as well as Russian olive (Elaeagnus angustifolia), tree of heaven (Ailanthus altissima), and salt cedar (Tamarix spp.)—but a permit is required to remove one with a diameter greater than 12 inches. While some residents consider it a fine shade tree, plumbers, park managers, and the Santa Fe Watershed Association want it gone. Seedlings are usually easy to pull and make good forage, but mature trees are notoriously difficult to kill. An environmentally friendly method is to girdle the tree and leave it standing. Birds, bats, and beetles will enjoy the snag for years to come.