The Beekeeper’s Companion Since 1861
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The Curious Beekeeper

Invasion of the Honey Plants

- June 1, 2021 - Rusty Burlew - (excerpt)

It’s not surprising that beekeepers are often in favor of invasive plants that “normal people” find objectionable. After all, honey bees are themselves invasive. Once they landed in North America via the Jamestown colony, honey bees lost no time distributing themselves across the continent. They engulfed the wildlands in a fashion that defines invasive, thriving not only where you put them but everywhere else, reseeding themselves wherever they felt at home.

Some of the contemporary articles explaining why we should preserve invasive plants for honey bees are downright embarrassing. A few authors openly state we must allow the destruction of natural environments and the loss of biodiversity so beekeepers can prosper. They present this philosophy as “being for your own good.” After all, where would you be without honey bees to pollinate your fruits and vegetables?

I have no objection to honey bees, just as I have no objections to other livestock, but there is an appropriate place for everything. We don’t seed the wildlands or destroy native environments so growers of pigs and cows and chickens can prosper, so why should we do it for beekeepers?

The real problem with native species

Beekeepers sometimes miss the point about invasive weeds and the problems they cause. The issues are subtle and can be difficult to understand, especially since bountiful crops of starthistle or Japanese knotweed honey are easy to understand. In many cases, invasive weeds make the year’s profit, the only thing keeping a beekeeper in the black. But are weeds that displace hundreds of native species the best thing for bee health? I think not.

The ultimate problem — and one that affects both native bees and honey bees — is that invasive plants create monocultures. The word monoculture simply implies that one crop (or one weed) grows over a wide area to the exclusion of all else. For bees, the monoculture is a one-trick pony, blooming all at once with a single amino acid profile in the pollen.

To illustrate, let’s go back in time and visualize what might have grown in a place when it was wild. In most undisturbed areas, whether they be prairie, grassland, forest, or even desert, you have many species of flowering plants. Each of those species — and there may be hundreds in a small area — blooms at a different time, and the pollen of each has a unique array of nutrients.

For bees, this means that something is always in bloom. One species follows another, sometimes covering season after season, so there is always something to eat. And those foods — in this case, pollens — are each slightly different, which gives a bee the wide range of nutrients it needs to thrive.

The spice of life

When you think of a human diet, you know we must eat a variety of foods to stay healthy. In fact, we’re taught to eat multiple sources of vitamins, minerals, carbohydrates, proteins, and fats. It’s difficult to be healthy if we eat just one thing at a time. Carrots, oats, and salmon are all rumored to be good for us, but if we ate just carrots for six weeks, only oats for six weeks, and salmon for six more, chances are we wouldn’t feel great by the end of eighteen weeks.

A limited diet can be harmful because no single food has all the nutrients we need. In a natural environment, we would eat whatever we killed or caught or dug from the ground, things like berries, leaves, tubers, bugs, and fish. Our foraging diet might not have the bounty found on a super combination pizza, but it would definitely have variety.

Honey bees also need variety. Very few plants produce pollen with all the amino acids honey bees need to thrive. In an environment with many flowers going in and out of bloom during the season, this is no problem because what one plant lacks, another plant supplies. So just like the variety in our chef salad or chicken stew, the bees get a cornucopia of nutrients from a panoply of sources.

One and done

However, the model of variety goes to pot when an invasive species takes over. Invasives displace so many plants that it becomes difficult for bees to eat a balanced diet. Instead of getting a large variety of pollen types overlapping over many weeks, bees get heaps of one pollen type followed by nothing. This is an impossible situation for wild bees that can’t fly very far, but it’s even difficult for honey bees.

Similarly, when we encourage the growth of invasive weeds in our beekeeping environment, we may increase our honey harvest but decrease honey bee health. Certainly we are harming wild bee species — those with short foraging ranges and no beekeeper supplements — and we are damaging other pollinators such as butterflies, moths, hummingbirds, and flies.

Without the plants that sustain them, many organisms disappear, causing entire ecosystems to collapse. Insects and spiders along with the birds that prey on them may disappear in addition to the soil organisms that decompose them. Take away one flowering plant and an entire network of life can collapse along with it. The amount of damage multiplies with each additional loss until the ecological upset is unfathomable.

I’m not saying invasive weeds are the fault of beekeepers, and I’m not saying I haven’t benefited from invasive weeds myself. But I draw the line when I hear of beekeepers collecting and saving invasive seeds, replanting weeds where governments are spending hundreds of thousands of taxpayer dollars to control their spread. Not only is it unethical, it’s also short-sighted. Those who seed invasives are not doing themselves, their bees, or our environment any favors.

An invasive honey crop near you

Unfortunately, honey bees often do well on invasive species, many of which have multiple advantages over native ones. With few natural enemies to weaken the invasives, they often thrive under conditions where the native plants fail — and the honey bees are quick to notice.

So what are these crops that beekeepers find so appealing? Honey-producing invasives span the continent, displacing old-time varietal honey with the flavor du jour. There’s something for everyone, so the list below is just a sampling.

Chinese tallow

The Chinese tallow tree, Triadica sebifera, is systematically swallowing the American southeast. Also known as the candleberry tree, chicken tree, or popcorn tree, the Chinese tallow is now considered an invasive species in most areas in which it grows. The Mississippi Fish and Wildlife Foundation calls it “one of the ten worst invasive weeds” in the state, and it’s officially noxious in Florida, Louisiana and Texas, too. The tree has become particularly problematic in eastern Texas where it grows in stifling regiments.

A member of the Euphorbiaceae family, it grows 30 to 50 feet tall, prefers full sun, and thrives in USDA hardiness zones 8-10 where it can flower as early as February. Historical rumor says a botanist friend of Benjamin Franklin introduced the plant, a native of eastern Asia, in 1772.

The sap and leaves are poisonous, causing skin irritations. In its homeland, the waxy coating of the seeds — which is not poisonous — was used for making soap and candles. The tree is deciduous and in autumn the leaves turn striking shades of tangerine, crimson, and plum.

In spite of its negative attributes, the Chinese tallow produces large quantities of high-quality honey in many areas of the south. Colonies can produce up to 200 pounds of the light brown honey with an herbal aroma and pleasant, spicy flavor. Beekeepers often move their hives into tallow tree areas in order to harvest the bountiful crops or to build colonies for pollination service. On the other hand, Chinese tallow readily out-competes traditional bee forage such as buttonbush, eastern redbud, and red maple — a sad loss of biodiversity.

Japanese knotweed

We all know that Japanese knotweed is an invasive species, prone to tearing up your driveway, cracking your foundation, and choking rivers and streams. But what’s the best thing about knotweed? That’s easy. It’s in bloom when nothing else is, at the very moment when no other plant is even thinking about it.

Japanese knotweed, Reynoutria japonica, is an herbaceous perennial in the knotweed family, Polygonaceae. Many people think it is a type of bamboo because of its hollow stems and raised stem nodes, but it has no relation to true bamboo, which is actually a grass.

The World Conservation Union lists Japanese knotweed among the top 100 worst invasive plants. But if you can look past that detail, it is actually a pretty plant with large spade-shaped leaves and showy cream-colored flowers. The plants may grow 5-8 feet tall in a dense bush-like display.

During late summer, you can hear these bushes before you see them. They vibrate with pollinators, especially honey bees. Many beekeepers harvest the ….