Fireweed (Chamerion angustifolium) is branching and delayed flowering

Observation by Gillian Brubaker:

My son took these pictures in my yard of the fireweed (??) that have multiple stalks and branching. At least we think they are fireweed. We are curious because of some of the other recent posts that were submitted to LEO from both Anchorage and Ester, also of weird fireweed. Can someone help us to confirm the species? Also wondering if this is some kind of larger event.

Comments from LEO Editors:

Earlier in the summer, LEO received two observations of fireweed with multiple blooming heads. In an observation submitted by Holly Dean in Ester, Matt Carlson, Director for the Alaska Center for Conservation Science, wrote:

"Those photos look like the primary flowering shoot was damaged in development (pulled off or moose eaten or something). When this happens the hormones coming from the growing tip down the stem that repress lateral bud growth are interrupted and the side branches go wild. This is the same phenomenon when you see “broomed” willows – where moose have eaten the terminal buds and it causes a much bushier growth form."

This may be a similar circumstance in which moose or another animal ate the flowering heads of the plant, which did not recover during the season.