LAKEWOOD, Colo. — Colorado Department of Agriculture (CDA) will be recommending that the following three Watch List species be added to the corresponding regulated list:

Yellow flag iris – Iris pseudacorus (List A potential)
Additional counties have been alerting us to this species’ presence and movement. CDA believes it is enough of a risk to warrant regulation, and now is the time to act.

Tree of heaven (ToH) – Ailanthus altissima (List C potential)
This tree is the primary host for the invasive insect, spotted lanternfly, which can impact orchards and fruit trees. Strategy would be to add ToH to List C and allow counties to manage it for their local economy. Similar to other tree noxious weeds, we would aim to stop the buying, selling, and planting of this tree and would take a “do not replant,” passive approach to overall management.

Siberian elm – Ulmus pumila (List C potential)
This tree is becoming an issue along waterways. The approach would be similar for this species as with ToH.

If you have concerns with any of these species being added to a regulated noxious weeds list, please contact the CNGA office.

–Colorado Nursery & Greenhouse Association