What we call fireweed, or stinging nettle, here in Florida has leaves similar to a strawberry pant that are covered with tiny hairs that irritate and burn the skin. The burning sensation can last for days. If the hairs are ingested, they can cause breathing problems and allergic reactions. It's quite dangerous for horses. I am assuming it's a different plant than your fireweed, which sounds quite lovely. I've never seen a flower on our fireweeds. Interesting that we have a plant with the same name but which are so different.