Fireweed offers a premium, late-season nectar flow for beekeepers who can handle its unpredictability

By Alison McAfee

May 1st, 2020

In 1920, when Frederick Dundas Todd, British Columbia’s first provincial apiculturist, toured the remote valley near the village of Telkwa, he left with the awe of a prospector who had just struck gold. Telkwa is located in a sparsely populated region of BC, just several miles southeast of Smithers and about as far north as the southern tip of Alaska — too far north for sustained agriculture.

“I left the valley with the feeling,” Todd wrote, “that I had seen a region that some day will be the heaviest honey producer of the continent, a district where a man could put down all the hives he could personally manage in one spot and get a big crop from them all.”

The crop he was referring to is fireweed honey. Fireweed, which is one of the first plants to colonize after logging or burning, can be marvellously productive. Todd illustrated this with an impromptu flower dissection: On a drive through the mountains, he stopped to pinch the flower’s delicate petals, splitting it in half to see what reward is offered by its nectaries.

“Just look at that blob,” he wrote, “a big drop of nectar caught at the bottom of the stamens and pistils; it must be itself a load for a bee.” But despite lucrative yields at around 200 lbs. of water-white honey per hive that year, a few years later, honey production from the same region was “practically a failure.”

What gives? To this day, the fireweed crop is frustratingly unpredictable, and Telkwa never did become the “heaviest honey producer of the continent.” Unlike staple flows from robust, invasive plants like the Himalayan blackberry or Japanese knotweed, fireweed has the fickle flow of a sensitive, native plant. Add to that the fact that it thrives in remote alpine regions accessible only via rough logging roads, which also happen to be prime grizzly bear territory, and chasing fireweed starts to look like a risky gamble.

“We cannot find any indicators that [the fireweed] will yield nectar other than putting hives there,” says Liz Huxter, a long-time beekeeper in Grand Forks, BC, where she runs her business with her husband, Terry. Some beekeepers place sentinel hives in the mountains, and move the rest up if they start putting on weight. But the Huxters’ approach is to chase fireweed only when the expected opportunity cost is low.

“When it looks like the valley is going to be really hot with little chance of nectar flows, we try putting some hives in the fireweed,” Liz says. The fireweed flow is late in the season, from mid July to mid August. When they can catch it, it offers a beautiful honey that sells at a premium, owing to the effort, uncertainty, and perhaps an element of alpine terroir.

One reason why yields are difficult to predict is because it depends on many different environmental factors. Early springs are bad, because the plant invests too much energy in new shoots which may just be wasted in a subsequent cold-snap. Cold, wet springs are bad, because it is harder for the shoots and leaves to develop, causing the plant to burn through its energy stores and be less able to invest in sexual reproduction (flowers) later on. Low soil moisture in the summer is bad, because osmotic pressure is necessary for both blooming and nectar secretion. But too much soil moisture is also bad, because the plant will disproportionately invest in foliage, rather than flowers.

According to the late John Davidson, a former botanist at the University of British Columbia, a heavy winter snow paired with a mild spring, or light snow paired with warm rains in May or June, should tickle the fireweed’s fancy. The melting of a deep snow pack can provide moderate soil moisture well into summer, but in its absence, summer rains should do the trick. Unfortunately, it’s not uncommon for those conditions to be met, and to still have a poor fireweed crop.

“To try and predict a good honey flow with fireweed is a bit of a toss up,” says Rudi Peters, a beekeeper in Terrace, BC, not far from Telkwa. He has been targeting fireweed for almost a decade and agrees that ground water and summer rain are important, but that in his experience, ambient temperature is the dominant factor. “You don’t want temperatures above 24 C [75 F],” he says. Otherwise, “the nectar will dry out during the midday, allowing only for a couple of hours in the morning for collection.”

Fireweed is such an important flow in Canada and the Northern United States that some researchers have tried to better understand what triggers nectar secretion. In 1989 and 1990, J. P. Michaud — a then-graduate student at Simon Fraser University, now a professor at Kansas State University — conducted a series of experiments to see what made fireweed tick.

In the field, Michaud observed that average ambient temperature and the amount of sunshine correlated best with nectar production. When he varied the temperature of potted plants in the laboratory, he found that nectar production peaked around 24 C, at 8.7 mg per flower per day — about six times higher than the average yield documented by other researchers — then dropped off at higher temperatures.

But it gets complicated. The minimum temperature needed for nectar secretion changes depending on how sunny it is: If light intensity is low, like on cloudy, overcast days, the minimum temperature threshold to activate the nectaries is 19 C (66 F) — considering this terrain is often at 3,000-5,000 feet above sea level, that temperature is pretty high. On bright, sunny days, only 12 C ambient temperatures are needed. And as Peters pointed out, if the humidity is low and temperatures are high, secreted nectar can dry up, making that 8.7 mg reward inaccessible.

“I would get an eighty-pound gain [per hive] in one week and then we would get a heat wave — around here that is 30 C weather — and then you get five pounds, if any,” Peters explains. In that kind of heat, the flowers also desiccate within only two or three days, instead of five or six. “It is a beautiful honey, but it can be an extremely frustrating chase.”

Part of that frustration also comes from rapid changes in mountain weather. The Huxters recall one time when they dropped colonies off in an unexpected summer alpine frost, but were pleased when the weather warmed up and the nectar started flowing a week later, resulting in a surprisingly lucrative crop. That time, the moody weather in the mountains worked in their favor, but that’s not always the case.

As if summer alpine weather wasn’t enough of a gamble, some research suggests that fireweed’s nectar secretions also depend on the plant’s energy stores leading up to the bloom. For many plants, nectar sugars are produced in real time via photosynthesis occurring in adjacent leaves. But Michaud discovered that even when he stripped 90% of leaves from the plants, the flowers still produced over two thirds of the amount of nectar that they normally would. Stripping only 80% of the leaves actually had a reduced effect, with flowers yielding 58% of their normal volume.

So where was the sugar coming from? Michaud suggests that the sugars are ‘mobilized’ from the long-term energy stores in the root system or other parts of the plant, producing an emergency nectar supply if the plant is spontaneously damaged from pests like beetles, which can cause massive defoliation. The degree of mobilization seems to be proportional to the degree of damage. It’s not clear if this mobilization is also important under normal circumstances, but it does suggest that in some cases, current fitness depends on past conditions (i.e. the conditions during which the plant was able to store energy reserves in its roots) — a sentiment underscored by the fact that new shoots spring from buds formed during the previous year.

Tracking the temperature, light intensity, humidity, and soil moisture within the fireweed patch, coupled with data on honey yields, might let us do a better job at predicting the flow. Long-term monitoring would allow us to correlate the previous year’s conditions with the current year’s production, which is probably a key missing link in our predictions.

But energy storage in the root system has another purpose. It’s how fireweed continues living, underground, through the harsh alpine winters, ready to shoot up again in the spring. It can also lie dormant for up to fifty years after a clearing grows in, waiting for another deforestation event to re-open the area for immediate recolonization. But expansion of the root system — a form of asexual reproduction — is at odds with nectar production.

Both forms of population maintenance — sexual, through pollination, and asexual, through root expansion or fortification — take energy and nutrients. And if either of those things become limited, the plant will preferentially invest in its roots as a long-term survival strategy. Some researchers found that fertilizing the soil dramatically increased the number of flowers per fireweed plant, supporting the idea that sexual reproduction is favored when conditions are good.

Forest fires leave behind highly fertile soil, but as nutrient availability decreases over time and the fireweed is choked out by other species, the fireweed will begin to invest more heavily in its roots. This leaves a window of around six or seven years for honey crops: According to experienced beekeepers, it takes 2-3 years after a disturbance for the fireweed meadow to become sufficiently productive, then it will continue producing for several more.

Serious beekeepers, therefore, need to eventually scout out new plots, and it can get a bit competitive — both with other beekeepers and with bears. In Vancouver, fireweed country is just a two-hour drive from town. With all the challenges that come with chasing fireweed, sometimes it doesn’t seem worth it to pursue, but not everyone is in it just for the honey crop.

Darwyn Moffatt-Mallett is a beekeeper on Vancouver Island, B.C., formerly located just outside of Squamish. He has tapped into some other benefits of moving colonies to the mountains in late summer, even if the crop that year isn’t bountiful.

Darwyn Moffatt-Mallett and Michalina Hunter, owners of Green Bee Honey, electrify a heavy-duty wildlife excluder to keep their colonies safe. The smaller boxes on top of the full colonies are mating nucs for their selective breeding program. Photo by Darwyn Moffatt-Mallett.

“The elevation helped reduce the yellowjacket [wasp] issues at a critical time for winter prep,” he explains, whereas the colonies left in the valley were “getting hammered.” Moffatt-Mallett and his partner, Michalina Hunter, have also been doing selective breeding — a task that dovetails nicely with moving colonies to the mountains.

“We have been able to combine all of that with pretty successful late-season isolated mating in fireweed,” he says. Since the colonies they bring in are the only ones around, they can control both the drone and queen sources during mating. “The colonies have always come down looking great even if they didn’t make surplus honey.”

Fireweed honey is almost colorless. But one year, Moffatt-Mallett’s bees filled the comb with a thick, dark honey instead, despite fireweed being by far the dominant flowering plant. This was likely a crop of honeydew, owing to a heavy aphid infestation.

Fireweed honey is water-white, and beekeepers quickly sell as much as they can produce each year. Photo by Darwyn Moffatt-Mallett

Several species of aphids parasitize fireweed, with their populations peaking at the same time as the nectar flow. Aphids feed on fireweed sap and excrete excess sugar in droplets from their anus, poised for collection by honey bees and ants.

Honeydew is a prized product. What could be better than plant blood, pooped out by an aphid, then puked up by a honey bee? It is also one reason why fireweed honey sometimes appears darker than it should — a dark color doesn’t necessarily mean it’s fake, it just may have honeydew mixed in.

Peter Awram, a commercial beekeeper in the Fraser Valley, has been developing a library of monofloral and polyfloral reference honeys in order to develop tests to certify honest marketing. He has been using a nuclear magnetic resonance (NMR) instrument to catalog the composition of each honey, which will also help develop better adulteration tests.

“What we have seen so far in fireweed and mountain honey is really varied,” he explains. “Probably in a lot of samples we are seeing other mountain flowers as well as some honeydew.” He suspects that a lot of fireweed honey is also mixed with pearly everlasting, a native aster in the sunflower family. Since fireweed honey (and honeydew honey) can be sold for a higher profit, there is motivation to have some kind of quality assurance in place.

“I do think we can find markers specific for fireweed, but the issue so far is being certain of what we are seeing.” He says that so far, he doesn’t have enough samples of what he considers to be “primarily fireweed” to make comparisons.

We may not have had sophisticated NMR testing 100 years ago, but aside from that, it seems like little has changed. Beekeepers still struggle to predict good fireweed years, and are still sometimes surprised by crops that are “practically a failure,” when the conditions seemed to be so good.

With a bit more data, I think we could do a better job. But maybe the uncertainty is part of the fireweed’s allure — it adds to the adventure and dopamine rush when the move pays off. “My record weight gain in a single week was 160 pounds for a single box hive,” says Peters. “Wish I could duplicate that every year.” But if we could reliably predict it, after all, the chase would be much less exciting.

This article originally appeared in American Bee Journal.