Alaska’s classic summertime flower is about to burst into bloom

I am getting a lot of questions about there being little to no fireweed (Chamerion angustifolium) this year. I suppose some folks are wondering how we are going to tell when winter is supposed to hit without those white seeds from the open flowers telling us.

There may be fewer fireweed blossoms this year. I really don’t know. It is still a bit early for their prime display period. Fireweed does establish itself in freshly disturbed areas (like after a fire or volcanic explosion), grows like mad, peaks in numbers (sometimes in as little as 2 years, but more like 10 to 15 or so) and then moves on. I doubt, however, that these plants have disappeared from our area.

For starters, fireweed is a hardy perennial, not an annual. This means plants are around for more than one season. Fireweed generally spreads by producing root-like structures, rhizomes, that form and grow under ground. Rhizomes are capable of producing new plants. This is asexual reproduction. In fact, some years a freed plant may not bloom. It will reproduce via rhizomes. Last winter provided plenty of snow cover, so I don’t imagine those rhizomes had any problem making it through to this spring.

To ensure the continuation of the species, fireweed also produces sexually via flowers to make sure the plants can establish elsewhere, far away from the original plant. Here is how that works. Each fireweed plant can have 15 or more flowers. These end up as seed vessels, wrapped up in a protective sheath. When these open up, out explodes 300 seeds from each individual flower.

Count the number of flowers or sheaths on a stalk sometime and then do the math. A plant with 15 flowers produces 4,500 seeds. Ahh, but that is not all. Producing seed and getting them to a newly disturbed area was the trick.

There are little hairs on the tips of fireweed seeds which are impacted by humidity and help determine the height of the seed’s drift when caught by a breeze. You should be amazed to learn that fireweed seeds can travel over 175 miles. Given the great number of seeds and the distance they can move, one of them will surely drift to the ground and find a new area to start a new colony.

You know me. I like to know what is going on underground. When it comes to fireweed, those rhizomes are pretty cool. They make it so fireweed plants do not have to flower every year. Perhaps that is what is going on this year with a lot of plants.

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I read about a 4-year-old fireweed rhizome that was dug up for a study. It was a whopping 20 feet long and had an amazing number of buds, 56. Each one of these underground buds can form a new shoot for a new plant, literally a clone. At 4,000 to 6,000 seeds per plant, that one rhizome would have produced plants with over a quarter of a million seeds.

Fireweed seeds are easily destroyed by the heart of a fire or volcanic lava. Rhizomes, however, survive fires because they are underground. This is how fireweed can establish itself so quickly after a fire (or volcanic eruption).

Speaking of clones, it is not unusual to come across a fireweed plant that produces white flowers. These seeds should produce white flowers, but a part of the rhizome certainly will.

In any case, I don’t think Alaska’s fireweed is going away. These are tough plants, just like Alaskans.

Jeff’s Alaska Garden Calendar:

Alaska Botanical Garden: See what is in bloom (and could be blooming in your yard) at Join for all sorts of discounts and benefits.

The Annual Anchorage Garden Tour: July 30, noon-5 p.m. This is always a must-do, fun and a long, long tradition worth partaking in. Check out the details at the Anchorage Garden Club’s Facebook page. It’s your chance to see others’ gardens. Do not miss out.

Plant second crops: Start seeds outdoors. Lettuces, kales, even carrots and broccoli.

Jeff Lowenfels

Jeff Lowenfels has written a weekly gardening column for the ADN for more than 45 years. His columns won the 2022 gold medal at the Garden Communicators International conference. He is the author of a series of books on organic gardening available at Amazon and elsewhere. He co-hosts the "Teaming With Microbes" podcast.