The summer heat is on in eastern Ohio. Bees and beekeepers alike are feeling the effects of “the dearth”, a time when nectar and pollen sources can become scarce in the hottest weeks of the year. New beekeepers are often surprised to learn that it’s possible for bees to starve in the middle of summer. But why is this so? As a beekeeper, I’ve taken notice of a great many informative articles out there explaining the ins and outs of the summer dearth from the beekeeper’s perspective. But as a botanist, I can’t help but notice a missing piece to these discussions….. a deeper botanical understanding. If you’d like to expand upon your botanical understanding of the dearth, or even the botanical side of beekeeping, then this article may be for you. I’ll try to keep it short and sweet. The reason for the dearth is all about resource management in plants…. Water, to be specific.
Plants lose water in transpiration (water evaporating through leaves as plants breathe and photosynthesize). Every plant has safeguards and leaf structures that control this water loss to varying degrees. Flowering, fruiting, and seeding is not only an energy drain on plants, but the flower structures of most plants lose a LOT of their water in transpiration through the thin, delicate tissues of a blossom. Plants know this all too well, so MOST plants opt to bloom when it's safest for them to do so.... spring and fall, when weather is cooler and retaining moisture is not as pressing an issue.
Of course plants are opportunists just like animals. Some plants take advantage of the fact that there is less competition to be pollinated during those hot summer months and have evolved better safeguards in their physical structures to reduce water loss. The deep roots of the compass plant, the wispy leaves of yarrow, or the succulent leaves of sedums are good examples of this. But these water saving structures extend to flowers as well. This is where you see many plants blooming with tiny to nonexistent petals, in an effort to keep water loss to a minimum. Other plants, like sunflowers, only have one row of petals around the outer rim, while all of the true flowers are contained within the greater head. For those of you who are not botanically inclined, each great big sunflower head is actually a collection of hundreds of individual flowers clustered together in the center. All of these are efforts at reducing water loss through transpiration. Echinacea, and teasel are two other plants that follow this plan. Other plants that bloom in the heat of summer like Joe Pye, Iron Weed, and Boneset, have tiny petals and flower parts to minimize the surface area for water to evaporate from them.
All things considered, blooming through the heat of summer is a risk for any plant, so statistically; most plants still don't bloom during the hottest weeks. Not only that, but many plants that do bloom during the summer will withhold nectar in order to conserve water. This is especially true for non-natives. In short, having a yard full of flowers doesn't necessarily mean that your bees have nectar available to them. Therefore bees and other pollinators have to travel further to find the few that offer it regardless. Hence bees have a dearth to cope with. An abundance of summer blooming, drought tolerant plants that are native to your area certainly helps lessen the dearth, since they are adapted to your climate and thus far less conservative with nectar.
Other botanical factors in a dearth have to do with habitat destruction in urban/suburban and agricultural development, where the native plants that pollinators depend on during the dearth have become extirpated (locally extinct). Many of the plants that bees depend on during the summer dearth are locally native, but labeled as useless weeds and are repeatedly destroyed. This presents an excellent reason for beekeepers to allow for some “wild and weedy” space on their property, or to embrace protective measures against local habitat destruction. Another helpful measure growing in popularity is the designation of local “safe zones” for ALL our pollinators. On that note, we often forget that our European honey bees are immigrants here, sharing space with an additional 4,000 species of bees native to this continent. That's a lot of competition to consider, especially during a dearth. At any rate, this presents an excellent reason for beekeepers to become horticulturists.
While you don’t have to be a botanist or a horticulturist to be a good beekeeper, I’d wager that it can make you a better one! The best beekeepers not only understand the ins and outs of their bees, but they also understand the ins and outs of the neighboring links in the food chain. Our old earth cultures were very cognizant of the fact that one strand in the web of life affects the other, so they took a great deal of time in trying to understand the whole web. A similar approach not only benefits bees and beekeepers, but our planet’s entire ecology.
As a botanist, if you can obtain a more detailed picture of which plant resources reside within your hives foraging zone, you’ll be much better equipped to anticipate and adapt to localized dearths as well as seasonal ones. Being able to identify your local trees, shrubs, and herbaceous plants (wild or cultivated, native or introduced) will enable you to construct your own personalized foraging/nectar flow chart through the seasons. No worries; you need not go to botany class! This can easily be accomplished with the help of a few field guides (such as Peterson's or Audubon), a little observation, some light reading, and finally recording your observations over time. But keep it simple. The only info you need is the plant species, the month it blooms in your area, and whether or not it has nectar and/or pollen value to your bees. As a general rule, I only include species that are well-established, or abundant in the area. Not only will your own flow chart enable you to anticipate and plan for periods of low nectar flow, but it will give you a better idea of what your honey is made up of. As beekeepers, we're not only responsible for the hives on our property. Since honey bees have a foraging range averaging around two miles, we have a responsibility to increase our awareness of what's available to them, or what they might be getting into within that range and respond accordingly. What's growing in the woods beyond your property? Or that prairie up the road? What are your neighbors growing on their farm? What might they be spraying?
As a horticulturist, you’ll not only benefit from the boost in pollination of any crops you grow. You’ll also have the know-how to cultivate plants on your land to help fill those nectar flow gaps in support of your hives. In this regard, an emphasis should also be placed on cultivating honey bee-friendly plants. You may have flowers blooming at the right time of year, but that doesn’t mean they’re ones your bees can feed from. Plants often cater to specific pollinators, which means that in many cases your honey bees are not “in the right club” so to speak, as certain flower structures work like bouncers at the local tavern, preventing the wrong patrons from getting inside for a drink. As mentioned earlier, flowers don't always equal nectar for your bees. At any rate, surely you see that botany and beekeeping go hand in hand, while horticulture and beekeeping can make great bedfellows.
With a solid grasp on the botanical side of things, you’ll be a much stronger beekeeper and your bees will be less likely to play the “get out of dearth free” card on you. It seems we forget at times that the idea is NOT to have to resort to feeding our bees fast food. At any rate, the good news about it being the middle of August here in eastern Ohio is that the summer dearth is reaching its end. Goldenrod is beginning to pop followed closely by several species of asters, all of which bloom so abundantly that many beekeepers will be smiling comfortably as they begin their winter prep chores. That is, if you don’t mind the sweaty gym socks smell of ripening goldenrod honey. ;-)
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